Climate control problems? Read This!

[gadget73]

I figured I'd toss together something that explains basically how the climate controls work, and how to troubleshoot and repair common problems. This applies mostly to box models since I don't know jack about the climate controls on the aero.

Firstly, there are 2 different systems in use, standard climate control, and automatic climate control (often referred to as ATC). Identifying them is quite simple. Automatic climate control head units say "Automatic Climate Control" on them and the temperature slider has numbers. Non-ATC head units simply have hot and cold markings.

The inner workings of both systems are pretty much the same. Temperature control is done via a blend door. One side of the door has the heater core box, the other side has the AC evaporator. The door can be full hot, full cold, or somewhere in between. There is always engine coolant flowing through the heater core.

Air is pushed by the blower through the box with the blend door, and past that it goes into the air plenum. In here there are a couple of doors that direct heat to the floor, dash, or defrost or whatever mix is selected. These doors are controlled by vacuum motors attatched to the side of the plenum. This whole mess is located directly behind the center of the dash, if you look behind the radio area, the vacuum motors are probably visible. In the event of a loss of engine vacuum, the doors are positioned in such a way that all air goes out the defrost vents.

The big difference between ATC and non-ATC is what controls the blend door. In a manual system, its done through a cable connected to the temperature lever. On the ATC system, it is done with a vacuum motor. Vacuum to this is controlled by the interior temperature sensor. This device is located above the glove box. It samples cabin air, and adjusts the vacuum on the blend door to get the desired temperature. Inside the temperature sensor there is a rubber diaphragm, a bi-metallic plate, a spring, and a small cam. The bi-metallic plate warps with temperature, allowing more or less vacuum through to the blend door motor. The spring is controlled through the temperature lever, more tension = more warping. In the event of vacuum loss, the blend door motor goes to full hot.

stand by for the next installment which will involve fan motor operation and troubleshooting.

[gadget73]

The fan motor on both systems is controlled the same way. The motor gets full +12v all the time. Speed control is done by inserting more or less resistance in the connection to ground. For less speed, more resistor, for full speed the motor is connected directly to ground. The blower resistor is located in the air plenum, and is accessible from the engine compartment. Its basically behind the passenger side valve cover.

ATC systems also provide a second way of controlling the fan. In addition to the 3 manual speeds, there is an automatic setting. On top of the blend door box, connected to the blend door there is a second fan speed control switch. When the blend door is full hot or full cold, the blower motor runs full blast. As it moves closer to the center, the fan speed slows. The auto setting is only for fan speed, it will not disable the automatic temperature control.


Troubleshooting:

**note** all troubleshooting info assumes that the heater core is present, connected, and not clogged. It also assumes no modifications to the air plenum or any of the systems in the car, and that the engine has the proper coolant level. Please check to make sure nothing has been removed or bypassed before moving on to the other stuff. Removed or broken AC will mostly not affect any of this, though obviously it won't get cold.

Air moves to defrost when accelerating:

This is caused by a loss of vacuum. The system defaults to defrost as a safety measure. Common leak areas are the "soup can" under the hood, a cracked line for the soup can, the one-way check valve on the vacuum tree, or the thermal blower lockout on ATC systems. To track down the leak, get a vacuum pump and apply vacuum to the assorted parts. Replace the defective one.

Air gets hot under load:
This is an ATC problem, also vacuum related. Usually this is also accompanied with the air moving to the defrost vents. See above for areas to check.

Fan motor does not work in floor position
Another ATC bug. The thermal blower lockout switch has probably failed. This is the sensor looking thing in one of the heater hoses under the hood. It will have 2 vacuum lines and 2 wires hooked to it. The purpose of this device is to keep the fan from running when the engine coolant is under 120 degrees. To diagnose this, simply unplug the electrical connector and jumper the two wires. To resolve it, either replace the TBL, or simply bypass it. If removing it, the vacuum lines must be sealed off. Do not connect them together.

Poor heat, no heat, or temperature wanders:
ATC problem. The interior temperature sensor has probably failed or it is not sampling interior air. Essentially this sensor is just a calibrated vacuum leak, but the rubber diaphragm gets hard and doesn't seal properly, causing the blend door to stay towards cold. To test if this is the cause for no heat, simply pull the vacuum line off the servo under the dash. This will be located directly behind the glovebox. Its a gold can with a clear vacuum hose. If the temperature wanders, ensure the plastic air sample tube is connected and not full of leaves. Ditto on the sensor itself. The tube connects to a nipple on the firewall just above the passenger's feet and goes up inside the dash to the ATC sensor. If this is pinched, disconnected, clogged, or ripped, the sensor doesn't have good data to work on. Simple test for this is to see if air is moving out of the side of the sensor. Its also possible that small bits of leaves and junk have gotten packed into the sensor from being sucked into the fan over the years. See attached pictures for the blend door servo, the sample tube, and the ATC sensor. Pics courtesy of 86GmLsCoupe

No fan speed other than high:
Likely a bad connection at the blower resistor, or the blower resistor has failed.


L to R, pics are:
sample tube connection at the firewall. SOmetimes this is a white tube.

ATC sensor location in the dash

ATC sensor part number

behind the dash view of the sensor. The control cable is disconnected in this pic. Normally it will be hooked to the arm on the end of the sensor.

The blend door servo with the vacuum line plugged for diagnosis.

[FatNasty]

Good info! I'l need to put this in a tech article, and hopefully get some pics to go along with it.

[Tiggie]

Keep up all the good HVAC info and I mightbe tempted to get my ATC working again.



No fan speed other than high:
Likely a bad connection at the blower resistor, or the blower resistor has failed.
I have low and manual high, no mid-range and always low on "Auto". Does this sound like the blower resistor or something else?

[Chris84]

and don´t forget the swich for the vacuum-lines :)


i´ve tested the soup can, the check vavle, and this swich.... it´s the swich, unfortunately... ;(

if i disconnect the main vac-line and put my finger onto it, it holds the vacuum (i sat there for about 8 minutes) if i connect all the lines, i hear a hissing sound coming from the swich... and, after 30 seconds or so, i hear this typically "ping" from the soup can, when the air comes into it...

[gadget73]

Keep up all the good HVAC info and I mightbe tempted to get my ATC working again.


I have low and manual high, no mid-range and always low on "Auto". Does this sound like the blower resistor or something else?

I'd bet its a bad connection at the resistor. The medium speed taps in the middle of the blower resistor, so if low works the resistor itself isn't fried. Probably the plug is crudded up.

[gadget73]

and don´t forget the swich for the vacuum-lines :)


i´ve tested the soup can, the check vavle, and this swich.... it´s the swich, unfortunately... ;(

if i disconnect the main vac-line and put my finger onto it, it holds the vacuum (i sat there for about 8 minutes) if i connect all the lines, i hear a hissing sound coming from the swich... and, after 30 seconds or so, i hear this typically "ping" from the soup can, when the air comes into it...

yeah, unfortunately sometimes they go bad too, but its not as common as the soup can. Actually I think you're the first person I've known to have one fail. Lucky you :)

[1987cp]

Would info on the specifics of the climate control circuitry be found in one of the following manuals?

http://cgi.ebay.com/ebaymotors/1987-Ford-Car-Manual-Electrical-Climate-Control-Auto-g_W0QQcmdZViewItemQQcategoryZ6759QQihZ004QQitemZ14 0085261583QQrdZ1QQsspagenameZWD1V
http://cgi.ebay.com/ebaymotors/FORD-BODY-CHASSIS-ELECTRICAL-SERVICE-MANUAL-1987_W0QQcmdZViewItemQQcategoryZ6759QQihZ001QQitem Z110170470123QQrdZ1QQsspagenameZWD1V

I'm wondering since I saw this table of contents for a Town Car EVTM manual, and it doesn't look like it covers the heater function except for ATC (unless of course ATC was standard on the Town Car): http://pix.faxonautolit.com/1987TownCarEVTMTOC.jpg

[Grand Marquis GT]

Brought to you by Gadget, the resident HVAC master!

[gadget73]

Would info on the specifics of the climate control circuitry be found in one of the following manuals?

http://cgi.ebay.com/ebaymotors/1987-Ford-Car-Manual-Electrical-Climate-Control-Auto-g_W0QQcmdZViewItemQQcategoryZ6759QQihZ004QQitemZ14 0085261583QQrdZ1QQsspagenameZWD1V
http://cgi.ebay.com/ebaymotors/FORD-BODY-CHASSIS-ELECTRICAL-SERVICE-MANUAL-1987_W0QQcmdZViewItemQQcategoryZ6759QQihZ001QQitem Z110170470123QQrdZ1QQsspagenameZWD1V

I'm wondering since I saw this table of contents for a Town Car EVTM manual, and it doesn't look like it covers the heater function except for ATC (unless of course ATC was standard on the Town Car): http://pix.faxonautolit.com/1987TownCarEVTMTOC.jpg

Probably the first one, though I have never seen one of those particular manuals. The body/chassis/electrical one has a lot of info on how to work on the climate controls. The EVTM is more of a troubleshooting guide (well, it is called the electrical vacuum troubleshooting manual after all). The BCE book is the ultimate word on fixing stuff on these cars, I'd highly suggest getting one if at all possible.


And yes, the Towncar EVTM only has info for ATC. Manual controls weren't available on them that I'm aware of. Possibly on earlier models.

[Chris84]

yeah, unfortunately sometimes they go bad too, but its not as common as the soup can. Actually I think you're the first person I've known to have one fail. Lucky you :)

perhaps the reason is the odometer :)
it says 380.634 kms...:merk:

[gabegt90]

thanks thain this is good info to have since I have atc

[Nathan in MI]

Thain, was the interior temperature sensor the piece that you recently mentioned having replaced and then it failed again very soon after? What are the options when that happens? Seems like you'd have to have it working in order to be able to control the heat, since there's no physical connection between the temperature slider and the blend door, correct?

[gadget73]

Thain, was the interior temperature sensor the piece that you recently mentioned having replaced and then it failed again very soon after? What are the options when that happens? Seems like you'd have to have it working in order to be able to control the heat, since there's no physical connection between the temperature slider and the blend door, correct?

That was the new China made thermal blower lockout that exploded on me. The ATC sensor is pretty much required for temperature regulation, though I guess if its really problematic, it would be possible to switch out the cable on the climate control head unit for one out of a non-ATC car, and just directly cable operate the blend door. Once the vacuum lines for the sensor were sealed up and the vacuum motor removed, it probably wouldn't be all that hard to make it manual.

[Mercmarquis]

cool stuff, need to look at some of this for my car.

Oh... wait, I ripped it all out

[85MercPark]

Anyone done a swap to ATC?

[yucatec]

Dear Panthers,
Most of my non-automatic temp control is new but it has failed. The blower motor sometimes roars on high (without heat), sometimes no roar (no heat), sometimes the controls work perfectly. It may work better when I first turn it on. The longer I drive the more likely it is to fail. I am also getting a check engine light intermittently.

Some heat drifts out of the vents but no push behind the hot air.

Took it to my local mchanic and he could not get it to fail. He jiggled the wires, poked and prodded but the blower worked just fine pumping out, he said, air at 141 degrees. He also fixed a vacuum line that had come loose.

I pick up the car and everything's working fine. Warm as toast. I do a little shopping and start home. No blower and the check engine light comes on. Any ideas?

Donald McCaig

[gadget73]

hm, that doesn't really make any sense. The blower electrical circuit isn't connected into the ECM in any way, so I don't see why that should happen. There is some vacuum plumbing in the climate control, but on a non-atc car, none of it affects the blower speed. It will mess with the door positions, but it won't mess with the actual heat output. Thats controlled by a cable directly connected to the blend door.


there is a thermal limiter built into the fan resistor that will shut it down if the blower motor is pulling too much current. Perhaps the fan motor is dying? Still no idea why that should trip a check engine light though.

[1987cp]

You could always replace the ATC with manual controls. :D

[gadget73]

Most of my non-automatic temp control is new but it has failed.


You could always replace the ATC with manual controls. :D

*cough* :)

[yucatec]

Dear Panthers,
It's a new blower motor. If the check engine light is just a coincidence, what's the next best guess. I've a new blower switch. Might that help? Donald

[1987cp]

*cough* :)

:doh: :bolt:

[Lincolnmania]

donald, have the connections at the blower motor resistor checked.......the original plug was crispy and i was unable to find a plug that wasnt crispy, so i used some spade terminals.......i suspect the switch has failed since it's orig, but if not one of those wires on the blower motor resistor block might have come off.........you got the new switch i had sent out? also having a new blower motor resistor and a pack of windshield clips sent to you......keep me updated, kinda aggravating, had it working decent here when it left.

[gadget73]

hey scott, not sure if you saw it but rockauto has those blower resistor plug pigtails available. might be worth looking into. napa might be able to get them too.

[yucatec]

Dear Panthers,
More news on my heater. Talked with the mechanic today and he said everything works but the heater box itself is so corroded that the heat goes everywhere. I told him to aluminum foil and duct tape the box and I''ll take the car to Texas. When I get home I'll change out blower, switch, box, pigtail/resistor.

Happy New Year
Donald McCaig

[1987cp]

Heater box is corroded? They're mostly plastic ... I wonder where the corrosion is, exactly.

[gadget73]

the only thing thats metal in there is the mounting plate for the heater motor itself. The rest of the mess is plastic. Pretty sure the doors inside are plastic too.

[1987cp]

The doors on mine are definitely plastic, with metal levers to the temp blend cable and vacuum motors.

[curley]

Thanks for all the info. I need a little help with the AC side however. First, when I switch to AC if the outside air temp is above about 60 the system blasts me with HOT air. If the outdoor temp is below 45 it feels like its blowing in air from outside. I think I likely need some R12 but what else do I need? It seems to be the controls are a bit screwy. Also, last summer even with the controls all moved to cold or off I always had a hot draft at my feet. BTW, this is an ATC car, 1989.

Thanks all

Curley

[1987cp]

Ah, ATC blues. Glad I've never had to deal with that ...... Gadget actually posted a tech thread that may help .... looks like you found it, so hopefully you'll be on your way soon!

[gadget73]

If the AC compressor isn't running, you will most likely get warm air out of the system. The seals around the blend door probably weren't perfect 20 years ago, and they've gotten worse. It also sucks air in from right below the windshield. Hot air from the engine bay usually gets blown out there so thats probably some of the heat.

If your AC system is still R12 you'd probably want to see if there is any refrigerant in there. Probably its dry. If it is, I'd suggest an overhaul of the AC system, this would involve a new orifice tube, a new receiver/drier, new O rings on all the hoses, and a flush of the system. New hoses are also a good idea if you've got some bucks to spend. If you don't have the equipment to properly service an AC system, I'd suggest having a shop do this for you.

The hot air out of the floor vents is possibly a broken air door. In the air plenum there is a door that siwtches from dash to floor, and often the "hinge' breaks, letting air sort of go everywhere. Mine is busted, I just haven't been inclined to rip the air plenum out of the car to fix it.

[1987cp]

I'd add to that to make sure if it's recharged at a shop (especially with megabuck R12), to make bloody sure they pressure test the system before giving you the car back. I wasted all kinds of money in about '99 having a Ford dealer go through the system and replace all the O rings and recharge it, only to call them a couple days later asking why the system isn't cooling and be told "well, the condenser could have a leak in it ...." ... :arg: Come to think of it, I'm not sure they replaced the dessicator, either, which I've since been told is absolutely necessary most any time the system is opened up, and that a new dessicator must be installed within two minutes of removing the plugs it's delivered with or it's bad. Long story short, I don't think those guys should have been working on A/C systems.

[Nathan in MI]

If they have any idea what they're doing, they should have put the system under a vacuum for a period of time before recharging it, so that any leaks in the system would present themselves...sounds like in your case, they failed to do that.

[P72Ford]

I'd add to that to make sure if it's recharged at a shop (especially with megabuck R12), to make bloody sure they pressure test the system before giving you the car back. I wasted all kinds of money in about '99 having a Ford dealer go through the system and replace all the O rings and recharge it, only to call them a couple days later asking why the system isn't cooling and be told "well, the condenser could have a leak in it ...." ... :arg: Come to think of it, I'm not sure they replaced the dessicator, either, which I've since been told is absolutely necessary most any time the system is opened up, and that a new dessicator must be installed within two minutes of removing the plugs it's delivered with or it's bad. Long story short, I don't think those guys should have been working on A/C systems.


Any shop that is worth a damn will pressure check the system before they charge it.

Last year, I spent about $90 to get my A/C working well (blew 38*F). I replaced all the o rings with R134a units, removed the compressor and got as much oil out of it as possible, had it evacuated and charged. I bought a retrofit kit (just fittings and oil) for $30 too. It worked awesome. Later I installed an aux. fan to blow more heat off the condensor; it made little difference.

This year, I'm going to take everything back apart, replace the dryer/ acuumulator, the orifice tube, maybe the o rings (if needed; but I don't see any leaks), have it evacuated again, and charged. It cost me $50 to have it evacuated and charged.

Gadget, where can I get replacement hoses for my '90 car? Periodically check Egay?

[gadget73]

yeah I've gotten them from ebay, but they're actually listed at a lot of parts stores. There are different hoses by year. 85 and older sets are dirt cheap but totally non-interchangable with later models. 86-91 used the same liquid line. The suction and discharge lines from 86-88 interchange, and the ones from 89-91 interchange. The AC compressor changed in 88 and it uses different fittings.

[grandmarquisdriversince98]

Regarding climate controls.....One thing I noticed on my 88 Grand Marquis is that the vacuum hoses that go to the thermal blower lockout control the heat being sent into the AC. Mine are always plugged up and disconnected from the TBL otherwise it controls the doors in such a way that the AC starts blowing heat when you accelerate instead of cold air. It's not mentioned in the shop manual but I confirmed it by hooking mine back up and then taking it off to have the AC return to normal during acceleration. I think it was to get rid of excess heat detected by the TBL when the cars were new and ran cooler. The only other problem I ever had was with the AC relay that made the AC work intermittently.

[gadget73]

yeah those have leakage problems. Its not supposed to do that, but if its not holding vacuum, it defaults to hot defrost. Mine were sealed up for the same reason when I still ran a TBL.

[Rodentkiller]

I as you know I own a 90 Crown Vic with A/C non climate control. My heater/Defroster went kaput. The fan works and the doors switch from heat to A/C when I move the temp lever but no heat and defrost what could be wrong? Is it a vacumme problem as suggested in the article or is it something else?

[gadget73]

I as you know I own a 90 Crown Vic with A/C non climate control. My heater/Defroster went kaput. The fan works and the doors switch from heat to A/C when I move the temp lever but no heat and defrost what could be wrong? Is it a vacumme problem as suggested in the article or is it something else?

Just noticed this. Either your temperature control cable is unhooked or busted, or there is a problem with the heater core. Perhaps its bypassed or clogged. Non-ATC systems do not use vacuum to control temperature. Its a cable from that slider on the dash down to the blend door.

[DiVin3]

How do you get the atc sensor out

[gadget73]

How do you get the atc sensor out

remove the upper dash pad. Once thats off, the sensor is located above the glovebox, and has 2 or 3 screws holding it in.

[87gtVIC]

Two 7/32 bolts iirc. Not a nice location to reach.

[Mil1ion]

On the ATC system, it is done with a vacuum motor.


Except the 92 CV and MGM in which case it is controlled by a 12 volt motor attached to the ELECTRONIC blend door actuator

shown below

http://inlinethumb61.webshots.com/20796/2675744190012099056S600x600Q85.jpg (http://rides.webshots.com/photo/2675744190012099056poKQSh)

[gadget73]

apparently the 91 is also like this. The vacuum stuff applies primarily to boxes. I don't know the mysteries of the roundy car climate control disaster, other than I want no parts of it.

[sinistral]

thanks for this!
i went to test the TBL and realized the connector in the heater hose was broken, so was leaking coolant! clipped/bypassed the wires, a couple of golf tees in the vac hoses, and removed the broken piece of the t-connector and re-connected the heater hose. :)

when it warms up around here i'll probably pull the whole TBL and just get a coupling for the heater hose.

this forum is awesome. :clap:


Fan motor does not work in floor position
Another ATC bug. The thermal blower lockout switch has probably failed. This is the sensor looking thing in one of the heater hoses under the hood. It will have 2 vacuum lines and 2 wires hooked to it. The purpose of this device is to keep the fan from running when the engine coolant is under 120 degrees. To diagnose this, simply unplug the electrical connector and jumper the two wires. To resolve it, either replace the TBL, or simply bypass it. If removing it, the vacuum lines must be sealed off. Do not connect them together.

[chitownvic]

Issue with with My defrost.. My Defrost doesn't work, When I switch it to defrost it just keeps blowing out of the vents.. Thanks mangs..BTW Thanks for the thread gadget I can finally fix my "Floor" too

[chitownvic]

BTW before anybody links me to this thread I posted this cus I read the whole thread and couldnt find anything on just Defrost fuck ups..

[gadget73]

does it shift to floor when you set it there? if the air doesn't really shift at all and sort of comes out of everyplace all the time, most likely its a problem with the air doors in the plenum. When my car did this, both doors in the plenum had broken at the hinges, causing the doors to just flop around in there uselessly.

[chitownvic]

It shifts to floor when I put it there but nothing comes out..(Kinda just shuts off) But thats the least of my worries I kinda need my Defrost Haha.. When I put it on defrost and put it on high it blows hardbut it trickels out of the defrost vent an the most of it is coming out of the regular dash vents

[91waggin]

How do you know it's shifting to floor if you don't get anything? I think your first step is to fix the business with the defrost, because the diverter door hinges are probably FUBAR. Once you fix the hinges in those doors, you may get a better idea about what's going on.

[chitownvic]

Allrite will do.. Now, how do I get there?? Haha

[gadget73]

Bypass the TBL. Jump the two electrical wires together and the floor position ought to work. If you want to elimiate it entirely, unplug the vacuum lines and seal them up too. A squeeze of RTV to block them up should do the job nicely. Just let it cure before you start the motor.

[Andypot1985]

So where is this thermal blower lockout switch. I don't have the floor so i would like to replace it.

Thanks

[87gtVIC]

under the hood near the map sensor. Looks like a coolant flush tee bit with some vacuum lines and electrical hookups. Just trace back the heater hoses out of the firewall and you should find it.

[Andypot1985]

thank you! ill go look for it today

[game over]

i have a problem with my heater - when the car stands with the engine running - the heater works fine, but when i driving at 40 mph or faster it becames coldy. any thoughts?

[slymer]

the check valve under the hood just about dead center on the firewall that has one line going to the soup can and the other going through the firewall. That's probably in need of replacing. The vent system is loosing vacuum and it defaults to cold in the older cars. It should have one hose coming from the vacuum tree (plastic tube with a lot of lines coming from it) and two lines coming out the other end. Also, check the "soup can" on the driver side to see if it holds vacuum. If it has holes in it, it will cause the same issue. Also check for broken vacuum lines in all of this.

[gadget73]

Going cold isn't a vacuum leak. Sounds like you may need to replace the thermostat in the engine. If it is stuck open, the car will over-cool when driving.

[game over]

the thermostat is new. the previous has the same symptoms

[gadget73]

Do you have a temperature gauge in the car? What does it read? Is the coolant level low? Air in the system might cause this problem. Is it an automatic climate control car? Sometimes when the sensors fail, it can cause no/poor heat. Automatic climate control says so on the control unit, and it has temperature numbers on the scale. Non-automatic simply says "cool" and "warm".

[Piece-it pete]

I've had t-stats bad 'out of the box'. You might want to check it.

Pete

[game over]

Do you have a temperature gauge in the car? What does it read? Is the coolant level low? Air in the system might cause this problem. Is it an automatic climate control car? Sometimes when the sensors fail, it can cause no/poor heat. Automatic climate control says so on the control unit, and it has temperature numbers on the scale. Non-automatic simply says "cool" and "warm".

coolant level is ok. there is not a temp gauge now in my car, but last autumn it was overheated in traffic jam. but the problem comes earlier. the climate is automatic

[slymer]

coldy! bah... totally misread that. for automatic temperature control cars (boxes at least), if the wire breaks in the ambient temp sensor it will pull vacuum on the blend door and default cold. But if you get heat under good vacuum and loose it under load on the road, there may be junk floating around in your coolant system. If it clogs the heater core, but then gets a little more pressure and pushes it through... that could cause the problem. Also, air pockets in the coolant (not purged all the way) could also do that. This shouldn't be a problem after a few temp cycles though since the system is supposed to purge itself. The only thing I can think of is the thermostat getting stuck open and then slapping shut after getting cold. And yes... thermostats can go bad quick.

[gadget73]

open the glovebox and pull the clear vacuum line off of the gold colored can. That should force it to full hot. If it does not get hot, then you have different problems.

[game over]

trying to make conversion from auto to manual climate control. and have some questions about this. anyone did this? there is no questions about the conversion exept one.
is anybody has heater vacuum diagrams? need both - for automatic and manual cars.
thanks to all

[game over]

trying to make conversion from auto to manual climate control. and have some questions about this. anyone did this? there is no questions about the conversion exept one.
is anybody has heater vacuum diagrams? need both - for automatic and manual cars.
thanks to all

[pseudoboyfriend]

Is the ATC temp sensor actually located in the dash just above the controls? It looks different than the one you post pictures of.

[gadget73]

91 and maybe the 90 have an electronic climate control system that uses different stuff. Instead of the blue vacuum thing, they have something with 2 wires and the crinkle hose. Those have distinctly different problems, mostly stemming from an electronic blend door actuator that fails and causes the system to do stupid things.

[game over]

ok, guys, but my car is not '90 or '91
it's a '85 colony park

[gadget73]

yeah, but someone else asked about a 90-91 model :)

[game over]

ok. sorry. i haven't seen

[bumpassbjorn]

I've done this twice. Once on an 87 Colony Park and an 86 Colony Park. It is a pain in the ass to try wedge fat hands and fingers behind the dash.

[nfldfordltd]

Mine gave out blowing heat unless the outside temp was wicked cold (subzero F) so what I ended up having to do was unplug the big vacuum line from the temp blend door control motor and plug it with a pen (to prevent vacuum loss) when I wanted heat...so now I haz lots of heat or none at all. Kind of a PITA having to reach in behind the golve locker and pull the line and plug it or connect it depending on what I want the HVAC to do for me. Alas, it works. I'll have to get a sensor and get it fixed I guess...any suggestions on where to get one?

[Bigbullitt]

91 and maybe the 90 have an electronic climate control system that uses different stuff. Instead of the blue vacuum thing, they have something with 2 wires and the crinkle hose. Those have distinctly different problems, mostly stemming from an electronic blend door actuator that fails and causes the system to do stupid things.

Would those "stupid things" include making a repetetive "thunking" noise while moving the levers from off to vent to defrost? If so, what can I do to fix that? (By the way, it's not constant and may do it on vent one time, not on floor, then on defrost one day and not the next.) Weird.

[Mercury Rising]

I am going to convert mine to manual control, I know it must be possible.

[cruso]

I have read the thread and have gotten myself lost...I have a 1989 Lincoln town car base with automatic. All options on my climate control work EXCEPT the reg floor setting. No flow No fan. Is this the atc valve under the hood at the end of the heater hose? thanks brad

[gadget73]

yes, its the thermal blower lockout switch in the heater hose under the hood.

[cruso]

thank you..is this something I can find to replace or should I just connect the wires? And if I just connect will it affect any of the other atc functions? Wiring is all greek to me! Thanks again

[tjc78]

Just jump the connector with some heavy wire and forget about it. The only thing affected will be your floor setting will work before the car is warmed up. All that did was prevent the system from blowing air to floor when the engine is cold.

[gadget73]

yeah, bypass it. Connect the wires together and seal off the two vacuum hoses. If you want it gone entirely, the new heater hoses are typically not cut for the sensor so you can get a new hose, or a plastic connector to take it's place. You can replace it, but the replacement parts aren't built very well. I put one on my car and it exploded about 3 weeks later. You wouldn't believe how fast you can empty a cooling system when one pops. Does a great job overheating the engine too.

[marquisman]

Its like installing a new self distruct time bomb! lol