Redveroom

I 'm trying to rewire some of my neighbors' 87 Corvette (C60 manual climate control) component wires in the engine compartment. The main a/c fan and a few other wires cut and bypassed. He had the blower motor hooked up to a switch, I reinstalled a new resistor and relay and got that working, Then I moved on the main fan, (green/white wire was grounded), which kept the fan on every time the key was on. So I resoldered the green/white wire and placed a new relay in that socket. Now the fan comes on when the a/c is triggered, however, now I have no a/c clutch or blower motor, Both A/C leads are showing 12+ volt( the green wire when triggered and the ground constant +). If I jump the a/c clutch to a source and ground it works.

He's a retired Jersey Cop and fireman, just trying to give him a hand so he can enjoy Vette, being Neighborly.

Tx

Hot Rod Roy

Have you verified that the black wire at the compressor clutch connector has a good ground connection? If the black is not grounded, you'll see 12 v. on it when 12 v. is applied to the green wire.

There is a diode inside the clutch connector, so don't reverse the polarity at the green and the black wires! Green must be +12 v. only.

Redveroom

Hot Rod Roy, thank you for your response. The black wire is hot constantly without the green wire being energized. Also, I did notice one leg of the diode broken.

Hot Rod Roy

It'll never work that way! It's hard to imagine this could be an accidental situation. Somebody must have done some re-wiring and connected that black to a constant +12 v. You'll need to find that connection. The black must go to ground.

Can you fix the diode connection? The cathode (stripe) needs to go to the green. If Bubba connected the black to +12 v. then grounded the green, the diode is toast!

Redveroom

I'll test the diode, if good I'll resolder the broken leg until I can purchase a new one. Everything worked ( with the exception of the main fan staying on) until I messed with the main fan relay. Like I stated early the main fan relays' green/white wire was cut and grounded coming out of the firewall, with the other end on the relay socket not attached. It seems as if things went haywire as soon as I resoldered it to the original configuration.

Hot Rod Roy

There should be nothing in common between the main fan and the a/c clutch circuits.

When the a/c refrigerant pressure rises because the a/c is on, the main fan relay is actuated, but this has nothing to do with your question of +12 v. on the black wire of the compressor clutch! Ground must be ground!

Redveroom

Thank for your response again Roy, I'm not gonna be able to get to the car until this weekend, but in the mean time I ordered the clutch pigtail with the diode on it. When I do get to the car I'll try to track down how that ground wire became energized. Until then, thanks again for your help.

Redveroom

Sorry for the late response, But work schedule and College Finals had me a little tied up. Anyway, I got the blower fan working and the a/c working again. I first cleaned the ground I think its 104 (The one the battery negative is connected to) still nothing. Then I cleaned the ground under the evaporator. Next to the high-pressure switch. Kaboom! Bang! Badaboom! Huston, we've got lift-off. Everything worked related to the a/c system as it is supposed to. His prior mechanic had stuff hot wired and bypassed. My only terms were no hot-wire of bypasses if I help (Find the problem and fix it.)

Next Mission is the vent actuators, the main one is stuck on defrosting the windshield.

Thanks for your help Hot Rod Roy

Hot Rod Roy

Good job! I don't like hack jobs either!

First test: Are you getting vacuum to the a.c./heat control panel?
Easy test:
1. Start engine. Temp Cold/Hot control lever full left (cold position). Engine does not need to be warm.
2. Look at heater vacuum solenoid at the heater core (under the hood, right side). It should be actuated (shuts off coolant to heater core).
3. Move temp control lever to the right (warm position).
4. Heater vacuum solenoid should move outward (allows coolant to flow into heater core).
5. Shut off engine. Wait at least a minute.
6. Move temp control lever full left (cold position). (Engine off.)
7. Heater vacuum solenoid should be actuated, indicating vacuum reservoir, vacuum lines, check valve, and vacuum to control panel are okay.
8. Report back.