Just need verification on climate control unit prb

CaifanSC

SCCoA Member
My AC cut off two days ago while driving. I checked all fuses and they're ok. I tried getting the error code fromt he control unit but it doenst even perform the test (knobs on AUTO & FLOOR and pushing COOL+OT buttons and then WARM). The outsisde temp is reading at -40*. IM assuming my control unit is shot, but i just want to verify that with you guys and see if there are any other sugestions before i go a head and replace the unit.

p.s., a while ago i was also trying to replace the two light bulbs inside the unit and I found that they were ok. I checked the shop manual and it said that if the bulbs and the circuit for the lighting are ok, then the unit must be replaced, but since the unit still worked i lived without the lights...this is what also leads me to believe that the unit is shot. Any help is greatly appreciated
 
Multiple possibilities. you could also have a electrical problem that is screwing up the voltages to the CC system.

But most likely the unit has failed. Maybe it got wet?

Couple questions though. Can't you force the A/C on by putting it into MAX mode, regardless of the temp setting? Also you might try putting it in Defrost mode and see if the A/C clutch engages.

I ask only because if you are low on freon, the A/C won't work either. Did the odd temp readings on your display start at the same time as the A/c stop working?
 
Thanx for your reply mike...the weird temp readings have stopped. It now displays the correct temperature. The unit does absolutely nothing....regardless of the settin go either knobs or temp setting. Like I said, it doesnt even alow me to run the test to get an error code. The unit didnt get wet, as its been in the stock position all the time. I cant hear anything engaging (even the clutch) when moving the selector knobs. And as far as IM concerned, if you are running low on freon you start feeling that the AC cools less or takes longer to cool...and this didnt happen. Besides, would being out of freon prevent the CC unit to stop functioning (i.e. not letting me do the test)?
 
No, I don't think anything with the freon would impact the CC system tests.

i guess I would start with pulling the battery cables for a few minutes to reset all the computer systems. Then see if it does better after it wakes up. Tracking that down could be a real pain, and most of the point tests lead to either a loose wire, or replace the whole unit. Not much else to be done.
 
I managed to get another control unit from the junkyard and it does the same thing, so the control unit is OK. My next step is replacing the blower control module....in the shop manual they call it the Pulse Width Modulator...on early SC's I think its just a small sensor with three resistors, but on late models its a whole module. I'll do that and post a reply
 
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