On your car there is a wire that travels from the front of the car to the compressor which turns the clutch on. This wire runs along the actual A/C lines.

Off of that wire near the compressor and below the battery there is another wire which branches off and I think goes to the battery... but I'm not sure. When I touch it to the battery the fan in the front trunk area (beneath the spare) turns on.

Can someone please confirm proper hook up and/or wiring diagram?

Thanks,
Bryan

VPC has a large one with fusable link that connects to the positive side of the battery Bryan.

Thanks, could you be a bit more specific? What is VPC? What is the wire for? Why does my fan come on when I put it to the positive terminal on the battery even though the system is not on?

Bryan

Brian,
I have the install manuals for both VPC and DPD AC for 914s if you want them...just PM me with your email.
Here is one page out of the VPC manual.

Thanks for the attachments via email.

I am still confused. I have the VPC system with the plastic cone shaped piece under the spare tire. I'm guessing this system is in the 1975 models but may be in others as well.

I am still wondering where the wire goes that branches off the (compressor clutch wire) just beneath the battery. Can someone look at their car with this system to see where it connects to? Is there a relay in the engine compartment that I cannot see on the wiring schematic or am I just totally wrong and the wire that was there was incorrectly placed?

This is the only wire that comes back along the hose from the front of the car.

Thanks,
Bryan

If you have the plastic cone shaped condenser cover, then you have a DPD unit. The VPC had a metal box under the spare tire.


there are no relays in the circuit, other than the one on the AC unit under the dash. The switch in the unit powers both the condenser fan and the compressor clutch. I found that when I added a larger fan and an idle up solenoid it would not engage the compressor clutch. So I added relays for each circuit, both to increase the voltage, and to extend the life of the switch in the unit.

If you ground the wire and the fan on the condenser runs, then that needs to be connected to the same wire as the compressor.

Clay,

Thanks for the help

Anyone out there have a DPD system on their car that they can verify what other wire comes of the wire that heads to engage the compressor clutch under the battery tray? This would help greatly.

Thanks,
Bryan

The switch on the DPD system feeds both the condenser fan and the compressor clutch. That wire under the battery tray should be connected to the compressor.

Turn the key on, and turn on the blower in the AC. The condenser fan should start, and the compressor should click as the clutch engages.

If it doesn't, it is probably the wiring under the dash. There is a big metal relay for the ignition lockout. It has a tendency to go bad.