Climate Control Issues

[AshleyTheGreat]

I've been having a couple issues with the Automatic Climate Control in my 1989 Lincoln Town Car. I'll start by saying that I did read the sticky post by Gadget73 before posting this but wanted to see if I'm on the right track with this and see if anyone had any further advice or suggestions.

The first issue I am having is with the blower motor not working on the floor position when it's fully warmed up (about 10-15 minutes after starting). After reading the post mentioned above, we're going to try to test the thermal blower lockout switch to see if that's the issue. If so, we're going to try to replace it.

The second issue that I am having is the heat isn't really hot. I originally had issues with it overheating at the peak of summer and as the temps here in MI starting cooling down, it would still be running on the warmer side. The couple times that it started to overheat (Needle outside of –Normal-) I turned the vent on and cranked the heat on high to try to cool it down, it was hot like it should be. Within the past week and a half, I've had no issues with it running on the hotter side, runs just as cool as my boyfriend’s ‘88 but the heat reaches lukewarm at best, even on the highest setting. Based on the sticky, we've come to the conclusion that it may be that the ATC sensor has failed. We're going to pull the clear vacuum line off of the gold colored can and see if that's the issue. We'll also be checking for any clogging of leaves or other random junk that may have found its way in there.

Thanks in advance for advice and any other suggestions!

Ashley

[lincolnlarry]

Check to see if the heater hoses are getting hot. If it is something plugged, the heater core won't get hot and the sensor in the hose won't get hot enough to enable the blower to run.

[VicCrownVic]

Sounds like you're on the right track.
TBL, as you mentioned, is likely the cause of your floor option not working.
Since the car was having issues overheating is/was there junk in the cooling system? The heater core could be could be clogged or nearly clogged.
If the heater core not completely blocked and you drive with the heat off for maybe 10 miles, then turn the heat on and get hot air at first but it cools back to lukewarm then you may have junk clogging the heater core. Flushing the core may work but it could take a few flushes to get the junk out.

[AshleyTheGreat]

That could be a possibility because the coolant was nice and green in both the radiator and the overflow bottle when I bought it but it looks as if somebody had replaced the radiator and/or the hoses. We had all the fluids flushed anyway once we got it but we suspect the thermostat is sticking and might be why it's overheating. We're going to check the ATC sensor right now and Derek wants to check the hoses going into the heater core to make sure they are warm.
Should have some updates later tonight.

[AshleyTheGreat]

Update:
We've determined the ATC sensor does need to be replaced because once the engine was warmed up and we let it rev for a little while, Derek noticed the previously cold heater core hoses and upper radiator hose getting hot. We had it running and the heat was lukewarm as it has been for sometime. We then pulled the vacuum from the gold can behind the glovebox and voila: insta-hot!
I recall Sly posting on the sticky about adjusting the ATC sensor. Is that possible? If so, how would we go about doing that?

We have determined 100% that the TBL is defective as when it was fully warmed up, it still did not work. The clip on the harness was busted so it seems as if someone was playing with that before.

[sly]

the ATC sensor may be busted and need replacement. remove the dash pad. The cable from the temp control goes right up to that. There's a set screw that holds it in place on the sensor and there's a channel it sits in from the cable that can be adjusted. That's usually not the problem. The problem is the bimetal wire inside the sensor rusts and breaks. It could also not be modulating the vacuum and allowing full vacuum to the blend door actuator (that big can) which will make it blow "cold" instead of hot. Also, if you're not getting good vacuum to the system (switch from vent to floor and everything doesn't move pretty quick) you may have to re-run the vacuum supply line (solid black) to the controls like I had to do for the Lincoln I sold to sxcpotatoes.

[lincolnlarry]

Just bypass the TBL by capping off the 2 vacuum lines and connect the 2 wires together. It just keeps the blower off and the re-circulation door open before the water is up to temp. Heck the vacuum part might even still be working?

Haven't had to adjust the ATC myself but know it is here on the sight somewhere.

[gadget73]

The adjustment for the sensor is mostly a range thing. From memory here, you set the slider to center scale, and align the arrow on the blue part of the ATC sensor with the arrow on the black lever. The cable end has a slot with a screw to let you adjust it. Thats all thats for. It won't correct any gross control problems, its more for complaints about its slightly too cool or warm when set to say 70, not a "the heat completely sucks" fix.

[sly]

The adjustment for the sensor is mostly a range thing. From memory here, you set the slider to center scale, and align the arrow on the blue part of the ATC sensor with the arrow on the black lever. The cable end has a slot with a screw to let you adjust it. Thats all thats for. It won't correct any gross control problems, its more for complaints about its slightly too cool or warm when set to say 70, not a "the heat completely sucks" fix.

pretty much this. It's only about a +/-5 degree adjustment. The main point is that the vacuum source line is screwed (kinked/pinched) or the sensor is borked and needs replaced.

[DerekTheGreat]

Thanks for the replies fellas!
We took the dash pad off, saw the cable and adjusting screw but left it alone as I kinda figured it wasn't going to correct anything major.. Going to order a new sensor ma-bob & a TBL sensor and call it a day.

I drove her car this morning and it has some sort of small vacuum leak. We replaced that thing for the parking brake when it's in park but it still has this low volume hiss coming from behind the dash, sounds like it's just behind the cluster. Goes away under low vacuum conditions like when you're accelerating. Doesn't seem to affect anything so I'm not sure it's worth ripping the dash all apart, unless of course anyone has had this happen before?

Derek

[DerekTheGreat]

Also, not related but I've gotten a whopping two PM's and I've replied to them but nothing shows up in the sent folder???

[sly]

the little horseshoe valve for the parking brake release is supposed to hiss/bleed in PRN but seal in DD1.

you have to change your settings in the user control panel. Click Settings at the top and then General settings on the left. Scroll down to messaging and mark the line that says "Save a copy of sent messages in my Sent Items folder by default"

[DerekTheGreat]

Yeah, that valve is all set but there's a leak coming from somewhere else behind the dash while in OD, D or 1, just a very low "sssss" sound. My TC doesn't make the noise so just makes me wonder if there's something we need to worry about with hers. Your thoughts?

Oh, so then the people got my responses then?

[sly]

they probably got your responses. Might send again just to make sure after changing that setting.

you'll have to get under and see where the leak is coming from. It may be from the parking brake release actuator itself, one of the vacuum lines not making a good seal, the brake booster, or the horseshoe shaped valve not sealing well. It could also be coming from any of the HVAC vacuum lines as well. Check the area behind the ashtray. That's where the bulk of that is. It could also be coming from the HVAC controls.

[gadget73]

Just a warning with those TBLs, I bought one from the parts store some years ago and it exploded a month later. You wouldnt believe how fast a car will dump its cooling system out when that thing breaks open, but within 5 minutes it was seriously overheated. I replaced it with a simple connector and just bypassed it again after that. It had been gone for years before I thought to fix it, but that failed and its never going back in.