AC Problem
Thread Starter
Instructor
Joined: Jun 2007
Posts: 148
Likes: 49
From: Coral Springs Florida
AC Problem
Hi All
I have a 1989 Corvette. I'm having a ploblem with the AC. When the car is at a light it won't blow cold. When I'm moving it's fine. 1st Where is the relay for the fan in front of the AC. 2nd where is the switch for the same fan.
Thanks in Advance
I have a 1989 Corvette. I'm having a ploblem with the AC. When the car is at a light it won't blow cold. When I'm moving it's fine. 1st Where is the relay for the fan in front of the AC. 2nd where is the switch for the same fan.
Thanks in Advance
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If you mean the Fan in front of the Condensor, it's Relay is on the Fan Shroud - left side. Switch is in the left head between 1 & 3. Switch closes with a Coolant Temp of 228 degrees driving the fan. A/c uses/needs the Main Fan (behind the Radiator) only. ECM sends battery voltage to a switch on the High Pressure Line. That switch opens when the liquid line reaches 230 psi and the ECM then grounds the Main Relay. Switch recloses at 190 psi and the fan should cycle off. With 50 to 70 degree ambients, Main Fan should be cycling on/off. Above 70 degrees, Fan will probably be running most of the time. If it's how it left the Factory, idle Coolant Temps will run 205 to 212 with the a/c on or below the threshold for Main Fan operation with the a/c off as pressure is made instantaneously so the Fan comes on sooner and stays on longer. If yours is blowing hot air at idle, check pressures, Main Fan operation, Low Pressure cutoff with a Manifold Gage Set. Look for ice on Evaporator outlet. If the Main Fan isn't working as designed, disconnect the Harness from the Switch to simulate the open. If that turns on the Fan, replace the switch.
