Climate control problems? Read This!

[Toploader]

So you mean to tell me that when I have blower on high switch position (not on auto) and the temp slide all the way to the extreme left blue, which is 60 degrees, it will continue to blow on high no matter what the temp inside the car is?

[miamibob]

Unless I am misinformed - CORRECTAMUNDO!!!

[Toploader]

If that be true, how does one control the cabin temp?

Unless I am misinformed - CORRECTAMUNDO!!!

[miamibob]

Depending upon what temp you are comfortable with, use the temp slider or manual fan speed.

[Toploader]

So, let my brain take this in.......with the fan on high and the temp slider on 65, the fan speed should never slow down on its own, and if it does I have a problem electrically?...........and, if it's in the auto position with slider on 65 it will slow down when interior temp gets near 65?

Depending upon what temp you are comfortable with, use the temp slider or manual fan speed.

[miamibob]

Correct. If there is a change in speed, it may not be an electrical issue but probably would be. If you want constant speed, don't choose Auto. It would just be doing what it is designed to do.

[gadget73]

Exactly correct. Auto means auto. Lo/med/hi is the manual speed control. It stays at the speed you select as long as something isn't broken.

[Toploader]

Now the test begins!

Exactly correct. Auto means auto. Lo/med/hi is the manual speed control. It stays at the speed you select as long as something isn't broken.

[Toploader]

Took the blower motor harness apart, it was super clean, as was the resister harness.

[lincolnlarry]

Toploader,

Looking at the EVTSM. The blower motor is connected to the positive side at all times when system is on. The negative side is connected at all times through the resistor to ground to run low. This is why yours will run in low during this problem. To run in high the negative side needs to be grounded directly. This takes the blower resistor out of the picture for your problem. There has to be a bad connection between ground and the blower motor. This can be a bad wire or bad contacts in the high setting on your switch. You should be able to reproduce the low fan speed by shaking wires or fiddling with the selector.

Hope this helps, Larry

[Toploader]

Larry, Looks like it is the switch!......even in manual with high fan speed, it slows down to low, and then goes back up to high.

Toploader,

Looking at the EVTSM. The blower motor is connected to the positive side at all times when system is on. The negative side is connected at all times through the resistor to ground to run low. This is why yours will run in low during this problem. To run in high the negative side needs to be grounded directly. This takes the blower resistor out of the picture for your problem. There has to be a bad connection between ground and the blower motor. This can be a bad wire or bad contacts in the high setting on your switch. You should be able to reproduce the low fan speed by shaking wires or fiddling with the selector.

Hope this helps, Larry

[sinistral]

so it would seem i've got airflow thru the dash vents, regardless of lever position (floor, mix, defrost). what is likely the cause, vacuum problem or broken door? the bizarre issue is that when temps get cold outside, the windshield fogs up terribly and the system seems to make it worse, no matter the setting. i'm thinking maybe because it isn't getting full power up thru defrost?

fan, temp, seems to work fine. '85 CP w/ ATC (though I just use in manual mode).

[sly]

check the vacuum connections behind the controls. Make sure things aren't loose. (you can see most of it from under the dash behind the ash tray)

Inless a previous owner plumbed vac directly to the full panel and then to the blend door... I don't see why this would actually happen unless the vent lever is broken or the vent control switch box (that the lever attaches to, called blend door lever on parts sites - Motorcraft part YH380 - it works for the ATC in our cars and I'll verify this when I get home as I have a spare one) is broken.

[gadget73]

If its not going to hot air, its probably not a loss of vacuum. Not shifting is usually caused by broken air doors. At least thats what its been in the others that have had this issue. All of the hinges in mine were broken off. The actuators all moved, but the doors flopped around and basically did nothing. its a crap fix, you have to pull the plenum out, take it apart, and rebuild the doors with new hinges. As far as I know, you can't get the original parts, so it ends up being a rebuild using small metal hinges from the hardware store. Its a bit annoying, but it works pretty well once its all said and done.

[sinistral]

pulled the glove box and the control unit loose and everything looks fine and connected... ??

was wondering if the vacuum was too weak (not much from the 'primary' black tube when i pulled the white bundle connector), but then it seems everything i've read says it should default to defrost w/ loss of vacuum?

temp goes to hot or cold just fine and fan works in all positions: just the vent is always blowing regardless. defrost "kinda" works, and floor "kinda" works (vent blows for both). both will shut off when the other is selected. basically vent is always on, so majority of air goes there instead of floor or defrost.