Hi all. I am having trouble with the AC in my 91.

The 1st problem is that the blower stays on high speed (10) at all times. That's even when I adjust the setting down.

The 2nd problem is that the air flow stops blowing in the upper vents if I do a medium to hard acceleration. During this time, The air blows harder in the bottom vents. This all happens for a few seconds then flows back to normal.

Any ideas what the problems are? Thanks.

 

Have you checked the blower motor relay?

http://www.ecklerscorvette.com/corve...1988-1992.html

 

No relay for Electronic Air; rather a Blower Module which simply amplifies Low Voltage Signals from a Processor (called the Programmer) and sends them onto the Blower. A couple of things can leave it stuck on MAX: 1. Controls are simply no longer communicating a lower number. 2. A broken Programmer. 3. An internal short in the Module which has it pumping out full voltage full time. 4. Actual Blower Voltage is fed back to the Processor (Programmer) on a fused circuit (5 amps) and that fuse has opened. It's often labeled PGMR or something similar - look at your Owner's Manual. Check that fuse first. If it's good, check the input to the Module (mounted on the Evaporator Case left side). It should be a brown wire and at 1, have about 2.5 volts on it. If it's correct and cranking at MAX, replacing the Module should fix it. If it's not (full low signal is about 6 volts), it's the Programmer or the Controls. Troubleshooting either is better with a Tech 1 which will emulate the Controls and if it then works, you need a new Control Panel. If it doesn't, it's the Programmer.

Door position is controlled by vacuum. Most common fault for your symptom is a broken Vacuum Tank (which stores the vacuum it needs when the vehicle is accelerating) or vacuum line to that Tank. The Tank should be in the left fender well below the left headlight. Trace the vacuum line back to the intake plenum. Along the way, you will find a Check Valve - make sure it's not broken too. The Tank itself is checked with a Vacuum Pump. Bring it down to about 10 to 12" of vacuum and make sure it holds.

 

Thanks. I'll check it out.

 

SunCr, what do you make of this. I checked all fuses in Passanger side main fuse box. All fuses are good; Hoever, when I put my test light on slots 7 and 12, on either side of the fuses it does not light up. I even moved fues that I know are good into these slots and same thing.

Also, where is programmer located?