Need to identify this switch

redlightning93 on Sat July 24, 2010 1:36 PM

Year: 1995
Make: Chevrolet
Model: S10
Engine Size: 4.3
Refrigerant Type: 134A
Country of Origin: United States

I do not post here a lot.....mostly lurk and read to try to gain experience from this Forum. Still learning about automotive air conditioning and most of my experience is with my older Ford trucks so the GM systems are a little different for me. The picture is the back of the compressor on my Mothers S10 showing a switch that I assume is the HPCO switch but not sure. It is leaking and I just need to identify it so I will know what to ask for. Also, will the system need to be recovered before replacing it?

I have gained a lot from the advise on this Forum and look forward to spending many more hours reading and learning.

http://www.autoacforum.com/forumimages/100_2836.JPG

Cussboy on Sat July 24, 2010 2:50 PM

Quote
Originally posted by: redlightning93
The picture is the back of the compressor on my Mothers S10 showing a switch that I assume is the HPCO switch but not sure. It is leaking and I just need to identify it so I will know what to ask for. Also, will the system need to be recovered before replacing it?

I looked at your photo. That looks very similar to the part I had to swap from my bad GM compressor to my new GM compressor (on my '94 Suburban) just a few months ago, as the new compressor just came with a plug there.

Yes, you'll need to recover the refrigerant first, and evacuate and recharge after the repair, sorry !!! After recovering the refrigerant, there's a circlip that needs to be removed using circlip pliers (you can jsut see that circlip in your photo), then that sender switch just pulls out; it has an O-ring seal in a groove, sounds like you need a new O-ring there. Make sure to replace with a green refrigeration O-ring, likely under $1 at NAPA or CarQuest or the online sponsor AMA. Lube it with a little Nylog or refrigeration oil, re-install, evacuate and recharge. You may want to add a LITTLE refrigeration oil before installing the switch to replace what you think may have been lost.

I guess the good news is that you should be able to do this repair without actually removing the compressor.

Edited: Sat July 24, 2010 at 2:54 PM by Cussboy

redlightning93 on Sat July 24, 2010 3:32 PM

WOW....that pic sure got big! Thanks for the reply so do you think I could just replace the o-ring and not replace the switch?

70monte on Sat July 24, 2010 3:35 PM

I just bought one of those yesterday for a 99 Suburban I'm working on and yes you do have to have the system discharged to replace it. I paid about $20 for a new one. I can't remember the correct name for that valve. The best way is to get the system discharged since it has to be anyway, and then remove the valve and take it with you.

You actually probably don't need the valve, but the O-ring that is down in the hole that the valve sits in. The new valve comes with an O-ring but I don't know if you can just buy an O-ring or not. I would take the O-ring out and see if the parts store can match it if you don't want to buy a new valve.

Wayne

redlightning93 on Sat July 24, 2010 3:40 PM

Thanks Monte....I guess I should plan on an accumulator since I will be opening the system then.

TRB on Sat July 24, 2010 3:54 PM

I do believe Red is replaced with Blue now. They even make a converter plug if needed.

29-30016

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GM Tech on Sat July 24, 2010 4:05 PM

It's a Hpco switch- normally closed-opens at 427 psi= closes at 250 psi-- you just need a new o-ring...

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Cussboy on Sat July 24, 2010 7:03 PM

Just try for a new refrigeration O-ring. You won't need a new accumulator, or a new switch. If you're worried about moisture, just stuff a rubber stopper (e.g. Ace Hardware) in there while you go O-ring hunting.

TRB on Sat July 24, 2010 7:24 PM

Agreed, unless the switch is damaged one can normally reuse it with a simple o-ring swap.

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