Doug Carner

I am restoring a Canadian built 1969 442 and have a problem piecing back together all the a/c components. When I bought the car 21 years ago, the a/c brackets, compressor, and wiring harness were in boxes. I have fitted the brackets to the engine and they fit great so I believe they are original to the car. The compressor, however, i believe is the wrong one for my vehicle (see the pictures below). The adjustment bracket that bolts to the front of the compressor doesnt line up right and there is an extra wiring plug on the back of the compressor which doesnt give with my 442 wiring harness. I'm hoping some of the CO folks here might have experience with restoring the a/c systems. Do I need a different compressor or just a front bracket? What is the plug on the back of the compressor for? Can I use this compressor and just leave off the wiring for the plug on the back of the compressor? Thanks so much in advance!


I bought this bracket off another CO member and it doesnt fit my compressor. Do i have the wrong compressor or wrong bracket?

Do these numbers jive with a 69 442?

So close to lining up but yet so far. I believe this bracket goes to the compressor but is incorrect for my car since it doesnt align with my engine brackets.

This little post on the back musy have a plug to wire it up but i suspect its wrong for my car.

crimsoncolby

For what it's worth...I'm working on a '75 Chevy Laguna S-3 and trying to reconstruct the a/c wiring that's been cut. My compressor has that plug at the back of the compressor, too...and, has the pigtail wiring plug that is attached to it. Was at a local U Pull looking at a '77 El Camino and that compressor didn't have that rear plug. So, like you, I was wondering what was up? From what I can tell in the second photo where the wiring harness/plug are visible (with one black wire and two green wires), it would appear we both have the same connector. On mine, the black wire is the one that has a plug on the end and attaches to the rear of the compressor (just don't know the purpose of the rear plug). The thicker middle green wire is your power source and the outer green wire feeds a plug at the forward end of the compressor. That forward plug also has a black wire that serves as a ground and runs to the front mtg bracket bolt.

Will be curious to read what others have to say.

tdhill01

Hi Doug, I myself am going through some AC issues in my 70 442 but I figured I'd chime in on your thread. The compressor at least by the label is not an original Oldsmobile compressor from 1969. The Oldsmobile compressor stickers will show the word Oldsmobile on it and will give a 4lb rating not the 3.75 lb that your does. The pin off the back I believe is the superheat switch used in 1972(?) - a 1969 compressor will not have it. Though your compressor has the pin on the back it doesn't mean it won't work if you don't use the pin. The bracket you showed looks like the one that is used on the cars. I have attached pictures of how the 1969 Assembly manual setup looks. To me your AC compressor does not look like it's on the proper bracket for your year. I have attached a photo from this site that shows the proper brackets needed. Good luck in getting everything together.

Doug Carner

Thank you SO much for the input. After reading your comments I am sure that I have the wrong compressor, but have the correct brackets. I will start a search for the correct compressor now. Thanks again!

Doug

crimsoncolby

I think you're correct, Doug. That is the GM part number on my Chevy compressor...and, after Googling the number, shows it is correct for '72-'76 Chevy applications.

rocketraider

The pin on the compressor head is a superheat switch as has been pointed out.

GM started using that thing in the 60s on Cadillacs and other carlines started in the 70s. What it does: if you have a severe loss of refrigerant charge, the resulting low freon pressure grounds the pin switch (think how an oil pressure switch works). The compressor clutch wiring incorporates a "thermal limiter fuse" that blows when the pin switch is triggered, cutting power to the clutch to protect the compressor.

Great idea in theory. But the fuses had a bad habit of blowing unnecessarily and shutting down the car's AC. Having had a couple cars with those things I learned to keep a few of those fuses in the glovebox.

In OP's case, a generic replacement compressor may or may not have the superheat switch. If it comes with it, won't bother anything but devise something to disguise/insulate it.