The whole unit is useless for some reason.

My PCM went out last week and i put in a new one. Did a FULL reflash with my original OS and Tune.
Everything is exactly the way it was before (including the vin). and now the A/C controls are completely functionless. going from vent to floor or window does nothing. moving temp control up or down doesnt change the temp. pushing A/C, Recyrc, or Defrost does nothing (no light or engagement). But blower still works 1-5
The only thing i have found to get me in the right direction is the VAT relink. Which i've done countless times and it always says the PCM has been scheduled to Resink on the next power up and i needed to key off key on. But then says step 1 of 1 and doesn't say if it worked or not.

Changed the relay under the hood and changed the 30a in the dash. but no dice.

 

try pulling all your HVAC or anything air conditioning fuses related. Leave them out for atleast 30 secs and reinstall them.

 

never thought of that. should be like 3 or 4 of them. I'll give it a try.

 

No dice. unless I missed one. Still blowing hot air all day long and all controls are dead except the blower speed.
Still no temp control, Can't switch off vents, no rear defrost, no a/c, no recirculate.
Plan on going to San Diego the last week of Oct. So I gotta figure this out. I'll most likely have my nephew with me and can't have it blowing hot air all day.

 

"Went out", your PCM? It just died? Unless one of the pt.net members knows specifically why or what, PM Torque_Wrench and give him your phone number and when he returns to work on Monday maybe he can help point you in the right direction. He knows a lot of crazy crap working at a GM delaer and can get you the parts you need for great prices.

 

Well.

It stopped responding during the middle of a flash. couldn't ever recover it. Don't really know why or how.
But that's the same time my A/C stopped working. I most likely just need a new dash unit. but would like to exhaust other options first.

 

Right off the bat it sounds to me like your AC Control unit is shot. And this can happen for a number of reasons. Also, a bad mode or temp actuator motor can cause this also. You can also try to re-sinc the actuators but it takes the help of a Tech II.

The first thing I would do is try the re-calibrate the mode and temp actuators. It's a failry simple process and won't take a long time.

Next I would bank that the AC Control is shot.

Without me being there and having a Tech II, I would need more details.

BTW.....did you figure out why your PCM..."just died"

 

I'll take it in to see if someone can resync it.
I noticed the other day that only the driver side is hot, the passenger side is cold. But still only have a blower and not control over climate or switching from vent to floor or defrost.

as far as the PCM goes, i noticed some black on one of the wires that goes to the plug under the dash. Going to take a look at it.

 

When it needs recalibrated, does that cause the whole thing to go dead like it did? If you hit the buttons the lights don't come on and the compressor doesn't even try to engage.

 

No, that's usually a sign that your AC Head Unit is not getting power or not powering up for one reason or another. Most of the time when I see this in my shop, it means that the AC Control Unit is bad.