95 pa a/c problems

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.

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.

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....

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?

It is auto temperature

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.

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

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

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

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.

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

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.

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.

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