A/C problems
Thread Starter
Intermediate
Joined: Apr 2005
Posts: 25
Likes: 0
A/C problems
I have an 88 C4 coupe, for some reason my A/C use to come on whenever I would start my car. I would have to manually turn it off each time. Now the clutch is spinning on the compressor, but the blower has stopped. I put a test light on the connector to the blower and it's not getting any juice. Where should I check next?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
System uses a Blower Module mounted on the left hand side of the Evaporator case to control the Blower and to provide a ground for the Compressor circuit. You can begin troubleshooting the Module by checking for power - red from a fusible link - and it should have battery voltage at all times. You should also check the ground - Black - spliced into the Blower Motor Ground and onto the frame below it.
The Blower signal is from the Dash Controls on the Tan or Brown wire. At "1" it should have about 2.5 volts. At "10" about 6 volts. Output is purple or whatever is hot at the Blower and you allready know that it's dead. You might check it at the Module too - at "1" it should have 4 volts and at "10", 12 volts. If you have blower output voltage at the Module, check the Blower Connector for melted wires. The terminals are only crimped and really need to be soldered because the motor can draw up to 25 amps. Gotta feeling though that you need a new Module - especially if the compressor was running the minute you turned the key. It's used across the line, so go to any GM Dealer if Chevy tries to stick you with a Corvette "tax". NAPA has a stocking # also.
The Blower signal is from the Dash Controls on the Tan or Brown wire. At "1" it should have about 2.5 volts. At "10" about 6 volts. Output is purple or whatever is hot at the Blower and you allready know that it's dead. You might check it at the Module too - at "1" it should have 4 volts and at "10", 12 volts. If you have blower output voltage at the Module, check the Blower Connector for melted wires. The terminals are only crimped and really need to be soldered because the motor can draw up to 25 amps. Gotta feeling though that you need a new Module - especially if the compressor was running the minute you turned the key. It's used across the line, so go to any GM Dealer if Chevy tries to stick you with a Corvette "tax". NAPA has a stocking # also.
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Originally Posted by SunCr
Gotta feeling though that you need a new Module - especially if the compressor was running the minute you turned the key. It's used across the line,
They go bad in the caddys all the time.
Instructor
Joined: Jun 2006
Posts: 124
Likes: 0
From: Arlington Texas
I think there is a relay down there hard to get to under the hood next to the windshield water reservoir. This relay might be the blower module that SunCr is referring to. I had lost this ground on my '84 once.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Electronic Air (through '89) doesn't use a Relay - it's all controlled by the Module based on inputs from the Dash. For example, compressor is hot from the a/c fuse and the Module provides a ground when it gets a signal from the Dash. Dash will send the signal as long as the low pressure and high pressure switches are closed and there is a ground at the ECM. If any of those things are open, Dash removes the signal and the Module turns off the ground. Kinda of around about way of doing things with the '90 and up being a little more sophisticated(letting the ECM control a relay that powers up the compressor).
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski