95 pa a/c problems

[Cfrye66]

I have a 95 pa base, the control assembly doesn't light up at all. I replaced it and it's the same. The blower motor runs all the time on defrost. My question is could it be the blower resistor.

I would greatly appreciate if anyone has any idea.

[brcidd]

The blower runs all the time and defrost--does blower shut off when car is shut off?

Defrost means a lack of vacuum control- as in a vacuum leak-

you say it is a base model- does it have auto temp control? you stated display does not light up, so I'll assume you do- (but on a base model?)

Most common problem is the vacuum manifold port on the a/c controller behind the glove box- it needs to be bypassed if the vacuum leak is there.

Temp display not working is very common- normally a bad solder joint inside control head- take it apart and reheat all power points.

If blower runs all the time and runs down your battery when car is off- then blower resistor module in HVAC box underhood needs replaced- very common failure mode.

[Tech II]

If the blower motor runs all the time, even with the key off, and you have auto temp, then it's the blower control module....

[Cfrye66]

The blower shuts off when you turn the key off.
I just replaced the controller. The blower runs even when you unplug the controller
If car isn't running there shouldn't be any vacuum should there?

[Cfrye66]

It is auto temperature

[brcidd]

Since you replaced the controller (underdash behind glove box) - how did the vacuum port manifold look? You had to unplug it to change controllers- yet I suspect it is in this manifold that your problem lies- I bypass them almost always when vacuum failure occurs.

And no, there is limited vacuum left after engine shuts off- based on vacuum canister size- to be sure, run the engine while testing.

[Cfrye66]

I didn't replace the one behind glovebox it was the heater-A/C control assembly in dash

[Cfrye66]

The control assembly won't even light up,and can't turn it on or off or air,heat or anything

[Cfrye66]

I didn't replace the one behind glovebox,I replaced the heater-A/C control assembly.
The one behind glovebox,is that the ECM?

[brcidd]

The one in the dash is called the control head.

The one behind the glove box is the a/c controller, or sometimes called the a/c computer-- definitely NOT the ecm. Ecms don't use vacuum lines. or have rods connected to temperature doors.....this is the one that I highly suspect has the input vacuum leak (purple hose) at the vacuum manifold into the a/c controller. The nipples break easily after they age and sometimes turn to soft rubber mush- this is why I bypass the manifold- go inside the controller and splice rubber hoses (5 total) around the manifold and into their respected lines outside the box. If you have air on only defrost- then I'm 99% sure the manifold is your issue-- new a/c controllers are $400+ - rubber hose is $1 - it is your choice.

[Cfrye66]

Does the vacuum manifold operate the control head then, because the control head doesn't work at all? I examined the manifold and it appears to be in very good shape

[brcidd]

Did you take the manifold off (unscrew the nut and slip manifold apart?) The vacuum supply (purple) nipple will shear off inside the manifold- can't see it without removing manifold. And no, the control head is not run by vacuum.

[Cfrye66]

I took nut off and slipped manifold off, vacuum is good. I unplugged the electrical connection to the controller and repluged it in, air blew at floor first then vents then went back to defrost.
I think my problem is that I can't get the head to function,no lights at all,head is new.

[Cfrye66]

Updated: problems solved, when I put a new head on it was bad , I took the old one apart and did some soldering on it and got it to light up. Will send head back to be reworked