Climate control problems? Read This!

[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

[colognecapri]

I have a super clean 87 GM LS with ATC. The car has ice cold a/c and all vent positions work, however I have two issues:
1) On full heat, the heat is hot until the car is driven for about 10 mins or so and gets up to temp (there's no temp gauge though). At thiss point the heat goes at best barely lukewarm.
2) The heat is only hot at the full hot setting, and with a/c on, it seems like any setting but full hot is the same cold temp.

From reading this thread it looks like the temp sensor by the glovebox should be my first suspect, am I on the right track?

[sly]

yeah... and it's above the glove box under the dash pad. Remove the dash pad (4 screws in the defrost vents... be careful with those... maybe stick a magnet on it to catch it), one screw on each end, and all the screws under the lip on the dash face. Should be dead center over the glove box with a flex hose in one side, cable screwed down to it, and vacuum lines opposite the flex hose. those vacuum lines are a BASTARD to get free. Keep pulling they will come out.

But FIRST, look in the open hole and move the lever back and forth. If you can see the spring inside stretch and collapse as you move the temp lever back and forth, then it should be fine and your issue may be that the cable is not screwed down to it in the correct place. If you want more heat, move it to the heat side, loosen the screw, and move the cable a little more that direction. Then tighten down. If that doesn't help, the bimetal spring may be worn out and you'll have to replace the thing. it's called an Ambient Air Temperature Sensor on most sites, but look around for best price.

[gadget73]

Might be worth pulling the fat flexy hose off the sensor and making sure its not clogged up first. I've had those packed full of leaves before. If there is no airflow through that tube, the sensor doesn't operate properly. Even if it is the sensor, making sure that tube is clear is worth doing.

[colognecapri]

Might be worth pulling the fat flexy hose off the sensor and making sure its not clogged up first. I've had those packed full of leaves before. If there is no airflow through that tube, the sensor doesn't operate properly. Even if it is the sensor, making sure that tube is clear is worth doing.

Ok, I took things apart (loosened glove box door and removed dashboard upper pad)....I found the fat flexy black hose disconnected from the firewall so I reconnected it, it is very clean and nothing was blocking it. The climate control temp lever is moving the ATC control unit as expected....I am struggling to see too much more...there is one vacum line that is unhooked that I am trying to find where it goes but thats about it.

As per this thread, I also tried unhooking the hose from the gold colored can and the heat did indeed blow warm no matter where the temp lever was positioned. I am guessing this means I should probably move foward with sourcing a new "YH409" ambient temp sensor?

[gadget73]

With the vac line unhooked, its forced to full hot. The temperature control will have no effect with that disconnected. The way that sensor usually fails, it leaks vacuum internally and pulls the air door towards cold, and unhooking it makes sure that the poor heat is caused by the sensor and not a clogged heater core. Sounds like yours is indeed bad.

[sly]

you should test it though, hooked back up and see if it all works. The loose vacuum line is vexing though. That might be causing something else not to work as well. Which line is it? Got a pic? Also, if the flex hose was not connected, the thing won't work either, so definitely test it with everything hooked back up.

[colognecapri]

With the vac line unhooked, its forced to full hot. The temperature control will have no effect with that disconnected. The way that sensor usually fails, it leaks vacuum internally and pulls the air door towards cold, and unhooking it makes sure that the poor heat is caused by the sensor and not a clogged heater core. Sounds like yours is indeed bad.

Good, thats what I understood from your posts in the first page of this thread. When I was messing with it last night the car wasn't fully warmed up yet but I was getting reasonably warm heat from the registers where with it connected it was cold.

I suppose I should fully warm up the car and see if the heat from the registers is nice and hot with the vacuum line pulled to rule out other possible causes. Does the fact that the car has ONLY had heat with the temp control set to full hot for appox. 10-15 minutes after a cold start make any sense? I hate how the car doesn't have a temp gauge, but it has been so consistent in the past it seemed like their had to be some correlation to the engine temp to the climate, but on another thought, maybe it was related to the temperature in the car rising. Do the maximum cold and hot settings disregard the ambient temp sensor of does it still play a role in blend door control?

[sly]

since engine coolant is used to make the heat, yes. It will not be warm until the engine gets warm.

The temp control adjusts the ambient air temp sensor which controls the blend door position through vacuum. Without the ambient air temp sensor working right AND completely hooked up properly, the temp control will not work much at all.

[colognecapri]

Sly, the other pics I took didn't come out, but as you can see in the above picture hose is black with a white stripe and you can see the clear cylinder shaped end on it. It has a little plastic push clip that appears to hold it to edge of some of the inner dashboard plastic that I reattached, but I can't figure out where its supposed to connect to. It is currently hanging down in approx. the middle of the behind glovebox area.