AC compressor pressure switch, single pin?

[PlayingWithTBI]

Here's the 2-wire connector (arrow in blue), I ran another wire loom back to the cycling switch (arrow in red).

You must be registered for see images attach

Cut one of the wires (light green but it doesn't matter which one you cut) going to the cycling switch and wired it in (red wires).

You must be registered for see images attach

 

[Joe B]

On the back of the compressor where the OE switch went.

Do you have a part number? I found ACDelco 15-5687, but I cannot find any specs as to the PSI.

 

[PlayingWithTBI]

Then I cut the power distribution block cover lower part because of my WBO2 wires, added a piece of loom to cover the pressure switches wires to protect them too.

You must be registered for see images attach

Do you have a part number? I found ACDelco 15-5687, but I cannot find any specs as to the PSI.

I don't remember but, I got the switch and 2 wire connector at a local NAPA store.

 

[PlayingWithTBI]

I don't remember but, I got the switch and 2 wire connector at a local NAPA store.

I take that back, the NAPA one was the one that flew across the shop, ha ha.

O'Reilley's has a Murry pn35961 200 on 430 off switch.
https://www.oreillyauto.com/search/1988/chevrolet/c1500-pickup-rwd?q=35961

 

[PlayingWithTBI]

Previously I said 200 on and 350 off (or something like that), I edited that response. As I said it post #14 it s/b 430 off. That's the one I have in my truck now.

 

[90halfton]

You dont have to hook up that pressure switch on 88-90 models (trucks with no 'recirc' button an HVAC controller). Just cut off the connector and ground the single wire on the harness. The system will move from fresh to recirc 30s after the A/C is called for in Med/Hi, full cold, when on dash vents. If you ever want fresh air on the A/C, either move the selector to partal floor, put the fan on low, or knock the temp one notch in the warm. I have the switch installed, and ended up grounding it full time because I never need fresh air when I'm trying to maximize cooling. You have no control with the pressure switch installed. That switch is not a high pressure cutoff...only controls the fresh/recirc door.

Huh....replaced that switch 10 years ago and wonder why the recirc door hasn't worked lol. I just didnt hook the other wire to anything because of apparently bad advice

 

[PlayingWithTBI]

As @studigggs said, on the trucks that don't have a "recirc" button, when you turn the fan on to 2nd or high the door will close after 30 seconds. The original one-wire pressure switch opened that door when pressures got too high (>250 IIRC) to get warmer air flowing over the evaporator and reduce pressure. IMO that was a pretty stupid idea with no safety backup and I guess that's why later years do have a high pressure shutoff switch there instead. With that HP switch in my system, my recirc door still closes as it should after 30 seconds. I know this is somewhat redundant but, the point is you still don't have any safety backup unless you hook up the high pressure shutoff switch!

 

[Jujube]

I have a 1991 C1500. I have a recirc button. But on the back of my a/c compressor there is no switch and I can’t seem to find the harness if there is one. I’ve had the truck for about 7 years now. The previous owner had the compressor going to a toggle switch. Is that good or bad? How can I add a high pressure switch if I can’t find the 1 pin harness?


Sent from my iPhone using Tapatalk

 

[PlayingWithTBI]

How can I add a high pressure switch if I can’t find the 1 pin harness?

It s/b a 2 pin connector, the 1 pin is obsolete and only used in systems that don't have the recirc button. Just get a 2 pin high pressure switch like I mentioned above (post 14) put it in the back of the compressor, and wire it in series with the low pressure cycling switch (as shown above).

You must be registered for see images attach

Note: You may have a high pressure switch elsewhere in your system, look from the compressor to the condenser to the orifice tube. If no switch or wiring connector there then, I'd use the port on the back of the compressor.

 

[Jujube]

This is the back of my compressor.

You must be registered for see images attach

Sent from my iPhone using Tapatalk