A/C comp control?

[71C10Guy]

So I have had a manual switch inside my 71 4 seasons for a year now to control my compressor. I found out today there is what looks like a potentiometer off of a stove or something under the dash that will kick the compressor on or off. It does have a line coming off of it that senses temperature to control when the compressor kicks on, but I can't believe this is what came stock on the c10, unless there used to be a gear on the knob and the hot / cold slider moved it? If this is stock, what is the part called? Thanks!

Some pictures: https://imgur.com/a/9ZnSj3M

PS: sorry for potato quality pictures, phone is broken so using potato.

[Andy4639]

That was added by somebody at some point.

[71C10Guy]

Originally Posted by Andy4639

That was added by somebody at some point.

Thanks man,
If you know can you point me to the right part to replace then? I usually use the diagrams on lmctruck to find out what parts I need/ are called, but I can't find anything but the entire control panel. I guess they didn't make parts for it, it's just one expensive unit lol.

[Pro299]

There is a compressor switch on the factory setup if that's what you're asking. It's on the back side of the AC distribution box which is the first box coming off the heater. Can't be seen from inside but if you feel behind the box you'll find the cable attachment for selection of either air or heat (the middle of the three slides on your control). When the slide is moved to the left it opens the flapper to shut off heated air and open the air from the evaporator. It also has a cam integrated with the cable end that pushes a button on the AC switch. Just changed mine yesterday while putting in a new blower relay.

[71C10Guy]

Originally Posted by Pro299

There is a compressor switch on the factory setup if that's what you're asking. It's on the back side of the AC distribution box which is the first box coming off the heater. Can't be seen from inside but if you feel behind the box you'll find the cable attachment for selection of either air or heat (the middle of the three slides on your control). When the slide is moved to the left it opens the flapper to shut off heated air and open the air from the evaporator. It also has a cam integrated with the cable end that pushes a button on the AC switch. Just changed mine yesterday while putting in a new blower relay.

Thanks man, but it sounds like you're talking about a flap for hot/cold air control, while I'm talking about the automated switch that turns the compressor on and off.

Wait, I just thought of something that might make this all moot... Does the ac system used in these trucks need to cycle on and off, to keep the right pressure, or are they always on when cooling, no cycling? I might just be really dumb....

[Pro299]

Like i said. There is a switch. It's operated off the end of the cable that also operates the flapper. No cycling. Simple on/off. Available from Brothers (ACS6772) and probably others.

[Sheepdip]

Originally Posted by 71C10Guy

Does the ac system used in these trucks need to cycle on and off, to keep the right pressure, or are they always on when cooling, no cycling? I might just be really dumb....

On a factory A/C system the compressor runs continuously, the POA (Pilot Operated Absolute)valve keeps the evaporator from freezing and building excessive pressure. Most after market systems use a binary switch to basically do the same thing by cycling the compressor off and on.

They make a POA upgrade that fits in the space allowed on a factory air system to convert to a binary switch to cycle your compressor.

If your POA is a Delco brand it is non rebuildable if it is Frigidaire brand it is rebuildable and can be converted to 134A specs.

That's all I know about that.

[tj1970cst]

That looks like the thing that comes on aftermarket stuff like vintage air. It did not come from the factory that way.

[Stocker]

This thread has a bit more info about that switch. http://67-72chevytrucks.com/vboard/s...d.php?t=766996 Your cursing indicates you found the location of it though.

[Andy4639]

The electrical section has the wiring schematic's in color with all the right color wires to trace your mess with and figure out what you don't need.