High pressure A/C switch on a 92?

[682XLR8]

I looked at the 1992 Service Driveability and Emissions Manual. In section 1B-4 it says the compressor has a pressure relief valve instead of a high pressure shutoff switch which is supposed to open to atmosphere when pressure gets above 440 PSI (see red arrow). I would not depend on it, if there's still one on the replacement compressor. I know my NAPA new replacement didn't have 1 or it didn't work because it blew out the pressure switch (sounded like a shotgun going off) and tore out the groove for the snap ring holding the HP switch in. I now have the switch I posted above in my new AC Delco compressor and wired it in series with the LP cycling switch - been working fine ever since! YMMV

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Like a shotgun, bet that got your attention lol I looked up the switch you posted earlier, my local O'reily's can have it at their store by tomorrow afternoon

 

[PlayingWithTBI]

I have the new (not rebuilt) AC Delco compressor from Summit, and it has the snap ring/slug set-up, I'll post up a pic when I get home

Maybe looks like this?

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[PlayingWithTBI]

Like a shotgun, bet that got your attention lol

Yeah, it's a good thing that I have tan seats in the truck, you can hardly see the skid mark!

 

[unruhjonny]

I have a very original 1992 in the garage, and went to look at the recently disconnected compressor;
It has a cap where it looks like that switch might be added, but it does NOT have that switch.
The compressor only has a single two wire connector.

My compressor looks different than that replacement one pictured in post #12.

 

[682XLR8]

Yeah, it's a good thing that I have tan seats in the truck, you can hardly see the skid mark!

hahahaha!!

 

[682XLR8]

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OK, here's the new compressor. Can see the plug at the top, but what exactly is that brass fitting?

 

[682XLR8]

I have a very original 1992 in the garage, and went to look at the recently disconnected compressor;
It has a cap where it looks like that switch might be added, but it does NOT have that switch.
The compressor only has a single two wire connector.

My compressor looks different than that replacement one pictured in post #12.

I dug through the wire loom on the engine, and saw nothing to suggest a switch plug was ever there, no cut or spliced wires anywhere

 

[PlayingWithTBI]

OK, here's the new compressor. Can see the plug at the top, but what exactly is that brass fitting?

I'm not sure, that could be the relief valve the service manual talks about?

I dug through the wire loom on the engine, and saw nothing to suggest a switch plug was ever there, no cut or spliced wires anywhere

You may have to wire it in yourself. I did on my 88, I just cut the light green wire and ran one end to the HP switch and from the HP switch back to the other end. That way, if either the LP cycling switch or the HP switch opens up, the compressor will shut off.

BTW, check your air gap on the clutch. It s/b 0.20" - 0.30". I had a new one from NAPA set over 0.80" and promptly smoked itself within a couple weeks.

 

[someotherguy]

All the replacement R4 (pancake style) compressors will come with the slug instead of a switch. It's up to you to install the correct switch IF your particular vehicle utilizes one mounted in the compressor.

Richard

 

[OLD BLUE 88]

I just completed total AC rebuild on 88 K1500. The two wire pigtail ties into the pressure switch on the back of the R4. I grounded the unused 2nd end of the pigtail, which now allows the recirculate/max air door to operate for the first time in decades. The pressure switch wire breaks out from the larger harness that runs around the front of the block, not back towards the passengers side.

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