Help! auto a/c wont work help!

[phoenix]

alright i have a 1996 corvette i am having some problems with the A/C when you set the auto temp on (doesnt matter what temp setting) it sets the blower to 0. from what i understand it should never go to 0 it should be 1 - 10 and on the resistor it should be between 4 - 7 volts. now on manual mode it works fine as long as its on inside air, if you command it to mid or low it cuts off the compressor.

i have already replaced the programer, there is no codes and all the temp sensors seem to be reading correctly.

this car is really starting to get to me so any help will be great

Thanks​

 

[tonylong]

I think my 89 auto is similar. Mine will show 0 blower at first until the eng warms up to 140+ (if on heat), or for maybe 60 secs or so if on cool or economy.
What does yours do if NOT on cool? Just to see if the problem is Cool-related or universal.
Any other odd probs like Temp controls lights blinking off, or the Temp resetting to 75?
I did have a prob related to the connector from the autotemp head unit to the connector (PITA) to access, I duct-taped it tighter, no prob since.

 

[phoenix]

temp has no affect on this conern, i have tried everything from 60 to 90, i am about to replaced the blower control module right now in hopes that will fix it. every time i shut off the car it resets back to 75 but i dont know if this is normal or not. There is no lights blinking, i do know there is some sort of vacuum problem cuz now it will only blow out the defrost.

 

[toptechx6]

A common cause for vacuum problems is the one way check valve located under the right side fuel rail cover. Remove the cover by lifting off and inspect the valve. It has one larger port connected to the intake manifold and two smaller ones that supply the A/C controls and cruise. Not sure it will cure your problem but it is worth looking at, the valve is under ten dollars and takes minutes to change. Failure will definitely cause defrost only air flow, good luck.

 

[tonylong]

temp has no affect on this conern, i have tried everything from 60 to 90, i am about to replaced the blower control module right now in hopes that will fix it. every time i shut off the car it resets back to 75 but i dont know if this is normal or not. There is no lights blinking, i do know there is some sort of vacuum problem cuz now it will only blow out the defrost.

Mine would reset to 75 and "econ" setting. That stopped when I pressed the AC head unit connector more firmly into the cable connector that goes into the bowels under the dash. May be indicative of loose connection.

 

[bill5674]

try unhooking the battery for a couple of minutes.It works on mine when that happens..

 

[JimBobC4]

try unhooking the battery for a couple of minutes.It works on mine when that happens..

I have pulled the fuse a few times to reset my AC head unit. Basically the same thing I guess.