Front AC Condensor Fan

[diablojota]

Hi everyone, I was hoping for some of the forum expertise here. I have a 1986 Porsche 911. Everything seems to be working just fine, except for the front condenser fan.

Here's what I've done:
- I have turned the car on, but not started. Set it to full evaporator fan speed and full cold on the thermostat. I can hear the evaporator fan come and it blows air, no problem there. I also have fans on my rear condenser connected to green wire on the compressor, and they kick on as well.
- I tested the power at the plug to the front fan. It's showing roughly 11.5 volts.
- I have a Zims adaptor with fuse in it. I plugged that in, still getting voltage through it.
- I can apply power to the fan and it operates.
- But, when I have it connected, it doesn't come on.

Any recommendations?

Thank you.

[walt]

Current draw from the fan may be too high indicating the fan motor may be on its last leg. Just replaced mine a few weeks ago. Those motors are still available and not too expensive at least not for my SC.

[pavegeno]

Any chance the front fan comes on with the compressor switching on?

[diablojota]

Walt, I appreciate that input. I guess I may have to try a new motor, though when I apply power to it, it runs great.

Pavegeno, compressor is on, the fan does not come on. I did make sure the compressor was on.

[walt]

So you have 11.5 volts available but it only runs when you wire directly to the battery, so I think you may have a current issue thru your existing wiring. Remove and clean the AC fuse and check the condition of the wires leading to the fan.

[walt]

Is this the type Zims adapter you used.

http://www.***********/store/front-condenser-fan-update-fuse-harness.html

URL does not work.

[RedCoupe]

Originally Posted by walt

So you have 11.5 volts available but it only runs when you wire directly to the battery, so I think you may have a current issue thru your existing wiring. Remove and clean the AC fuse and check the condition of the wires leading to the fan.

+1 this. Your battery voltage is likely something like 12.6, so there is some resistance in the circuit as Walt says if it’s measuring 11.5 volts without the load of the motor.

[diablojota]

Originally Posted by walt

Is this the type Zims adapter you used.

http://www.***********/store/front-condenser-fan-update-fuse-harness.html

URL does not work.

Yes. That’s the one. I have tested with and without the adaptor. It wasn’t coming on without the adaptor either.

[Steve Marshall]

Pull the fan housing and the fan. You'll have to pull it anyway to replace it. Put power to it and spin it with your hand and see if starts working. Probably want to squirt some oil into the bearing on the motor. If it's not fried looking I bet it spins right up.