1971 c10 AC wiring

[71C10Guy]

The wiring to my compressor is shot, somewhere. The last person that owned it decided to splice just about every wire on my truck, so going through the wiring has been a disaster, to say the least. I currently have my compressor wired to a switch on my dash that I flip on and off to engage the clutch. I was hoping someone already has a detailed thread on this, a wiring diagram, or a list of things that could be broken?
Thank you

[71C10Guy]

Also, where are these lines supposed to go? I have the line from the expansion valve wrapped around the upper line coming from the evaporator core, and the line from the pressure switch goes into the housing, but I am not sure where it goes? Thank you

[Steeveedee]

Pics?

[Bigdav160]

The compressor power is controlled by a small switch on the diverter box in the duct work.

The switch isn't a robust piece.

Follow the control cable from the control head to the box and you'll find the switch on the back side.

The expansion valve has a temperature bulb that is clamped the evaporator outlet. There is an oil drain line that goes from the evaporator to the POA valve. If you have a pressure switch someone has removed the POA.

[chooch]

boundstaffpress has a good wiring diagram at http://67-72chevytrucks.com/vboard/s...d.php?t=185856

[71C10Guy]

Originally Posted by Bigdav160

The compressor power is controlled by a small switch on the diverter box in the duct work.

The switch isn't a robust piece.

Follow the control cable from the control head to the box and you'll find the switch on the back side.

The expansion valve has a temperature bulb that is clamped the evaporator outlet. There is an oil drain line that goes from the evaporator to the POA valve. If you have a pressure switch someone has removed the POA.

Thanks you! This is great info, and I do have the POA valve, but since the wiring is obviously burned or disconnected somewhere I have an actual switch on my dash for simplicity. I am going to busy for a while, but I'll try following the cable to see where the switch is. Also, it seems to me that the tube running from the POA to the expansion valve would push the pin down letting more freon through the low side? And I guess the temperature of the coil that goes on top has an effect too?
Thanks

[Stocker]

Originally Posted by Bigdav160

The compressor power is controlled by a small switch on the diverter box in the duct work.

The switch isn't a robust piece.

Follow the control cable from the control head to the box and you'll find the switch on the back side.

Originally Posted by 71C10Guy

I'll try following the cable to see where the switch is.

Operate the top A/C slider control (left end is inside air, then outside air, and far right is defroster) to activate the switch. It's normally open and it closes (makes a connection) when the control slider is at the far left side (Inside Air). You can see the switch on the back side of the diverter box if you lay on the passenger side floor and look up. Might need a flashlight. Most vendors have the switch but they tell you it's behind the glove box which is kind of misleading. It's a simple on/off switch with two wires and it sends power to the compressor -- actually, iirc it goes through the switch on the POA valve.

[snipescastle2]

I have an extra a/c harness at home, let me look and make sure it's still there first, I'll send you pics of it and if you need the assembly manual drawings for wiring/hose/line routing I can snap a few pics as well.
Ben