Climate Control Issues

[nfldfordltd]

I had the same problem with lukewarm heat before (unless it was super cold outside), and it turned out to be the ATC sensor. I bought a NOS one online, installed it and now have good heat. I don't think it was very expensive either, can't remember the actual price now.
As for the blower not operating in the 'floor' position, I'm thinking that has to be the Thermal Blower Lockout switch. Nothing else it can be, really.
Overheating...that could be any number of potential problems. I sort of took care of that with mine by replacing the entire cooling system, pretty much at once. This included the rad, water pump, thermostat, gooseneck, all hoses, heater core, etc. It was actually not very expensive overall, probably around $300 altogether.

[gadget73]

mine overheated because the TBL exploded and dumped all the coolant out. Was a pretty obvious reason why, but after that experience I was not motivated to put a new one in, and just bypassed it entirely.

[DerekTheGreat]

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.

I read that from the sticky and got a good chuckle out of it I'm a stickler for keeping things as OEM as possible althought the thought of that exploding on her car while she's out somewhere has me worried a bit. I once drove a 7/8 cylinder Caprice that had coolant leak issues from Warren MI all the way to Flint MI. Didn't make it, the engine decided to to discard more of it's pistons about 3/4 the way up. The temp gauge on that thing behaved like my Firebird's so I thought all was well. Whoops. Anyway, I was going to have her buy a Motorcraft TBL and if that exploads then the old one goes back in bypassed.. Ever since I read these threads I've started using mine on the floor position and like that it automatically comes on. Floor & Floor+Defrost are my favorite climate positions in the winter. Parts should be here by Tuesday so we should have an update by Thurs or Wednesday.. I'm also thinking her car could have a stuck thermostat. Takes forever to heat up. Has other issues too but since she wants to do an HO swap I'm not sure how much money we should continue throwing at the LoPo...

[gadget73]

I've debated on re-engineering that TBL thing to not suck. The Mark VII part is a sensor in a metal pipe. The sensor itself can't directly sub for the TBL but it can drive a relay that can be used to switch the blower motor on and off, and if I feel like getting fancy, I could also drive a vacuum solenoid to control the fresh air / recirc door vacuum supply. I've been less than motivated though, mostly because I don't drive the car in winter anymore so it doesn't actually bother me any.

[DerekTheGreat]

Man, it sure would be nice to have control over the recirc door. Nothing like pulling up to a light only to have your HVAC system suck up some dudes cigarette fumes. Blech.

[sly]

I have control over mine... http://www.grandmarq.net/vb/showthre...l=1#post720706

[DerekTheGreat]

"...but it's better than suffering through a horrendously long light next to some douche rolling coal."
LoL

Yep, that's why I'd like direct control but since there's no factory authentic way to do it the car stays as is. I liked the manual set up in the LTD, max and regular at the flip of a lever. Now the way I understand the auto system is is you get recirc by maxing out the travel to hot or cold?

[sly]

yup. Supposedly. Never actually worked that way on mine.

[gadget73]

yeah, the valve is a bit sketchy and if the TBL leaks vacuum it doesn't work either. Mine works, but there is no TBL to leak. I don't know how well it actually does, but I expect its working about as good as its ever going to short of me tearing it apart and polishing the blend door shafts and such to reduce friction so that it moves a bit smoother. I don't care nearly that much though.

[DerekTheGreat]

Update:

New ATC sensor is in and Ashley says the heat is hotter than ever so that's one less problem her Townie has! TBL will be fiddled with as soon as we can find a Motorcraft unit.

Gadget,
The only way I know if recirc is working is that change in sound the vents make when switching from "vent" to "max" and of course the increase in air velocity. Will the auto stuff respond the same way by moving arm all the way to the left?

[gadget73]

yes, it goes into recirc with the temperature at either extreme. it will actually do this automatically too. If you set it to say 75, and get moving down the road on a 5 degree day it will run in recirc mode until the interior temperature starts to come up. As the blend door shift away from full hot, it will switch from recirc to fresh air. The fan speed will also drop as it travels closer towards the middle of the blend door range.

[DerekTheGreat]

Didn't know that, thanks for the info! Seeing as there aren't any wires feeding into the ATC sensor what controls the auto fan speed, vacuum? Also seems that when in auto there's a speed just above the lowest manual speed.. Another questions for you: Is it ok to leave the fan speed selector or climate selector lever in any position when shutting the car off or before you start it? I'm a big fan of turning everything off before I shut the car down or start it, but lately I've been leaving the selector on floor or floor+defrost and moving the blower to the lowest setting before I turn the car off because I don't want to wear out the selector mechanism.

[miamibob]

Didn't know that, thanks for the info! Seeing as there aren't any wires feeding into the ATC sensor what controls the auto fan speed, vacuum? Also seems that when in auto there's a speed just above the lowest manual speed.. Another questions for you: Is it ok to leave the fan speed selector or climate selector lever in any position when shutting the car off or before you start it? I'm a big fan of turning everything off before I shut the car down or start it, but lately I've been leaving the selector on floor or floor+defrost and moving the blower to the lowest setting before I turn the car off because I don't want to wear out the selector mechanism.

Think that might have true "in the old days". I leave everything alone and just shut off the car. Have never had an issue upon restarting!

[DerekTheGreat]

So you restart it with all of the accessories pulling power? That's the part that concerns me. Radios seem to get irritated by flipping to run for fuel pump prime then crank position for starting.

[miamibob]

I shut my stereo off only. My ATC stays in whatever position it was in when the car was running.