1999 Chevy Astro A/C compressor wont engage

POSTMOD

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1999 CHEVROLET ASTRO

Air Conditioning problem
1999 Chevy Astro 6 cyl Two Wheel Drive Automatic 256k miles

No power to the A/C clutch. Freon shows 150 psi on low side. Both relays are working. Low side pressure switch [on the drier] is also working. Wiring diagram shows 2 pressure cutoff switches. Can't find high pressure cutoff switch.
Thanks

3 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

The high pressure switch is in the back of the compressor, you also have an a/c clutch relay in the underhood power center, try swapping it with another to see if it will work

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Monday, May 4th, 2009 AT 2:14 PM

POSTMOD

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I could feel the relays click when they were installed and so I thought they were working. I jumped across the terminals and the clutch engaged. So the relay was in fact not working.
Both of my local auto parts stores did not carry this relay so we matched it up with a generic. The A/C relay was showing a $38 dollar list anyway at both stores, So good thing anyway as the generic was only $10. It's working fine now which is a good thing if you live in Texas. Thanks for reiterating the relay possibility.