A/C Prob - Compressor On-Off & Checked w/ Gauge

Hello all,

I have been lurking these forums for a while, and you all have helped me on many issues with my '97 Blazer. Thank you all. I hope you can help me now.

As mentioned, I have a 1997 Blazer LT. My A/C used to work slightly (after a few minutes), but never really made it really cool inside the vehicle.

I bought a recharge kit from Autozone and hooked up the gauge while the truck, and the A/C, was running. The compresser would turn on and off at intervals.

The pressure would reach approximately 60-70 psi, then the clutch would start spinning. The pressure quickly drops to 20psi, and the spinning stops. The pressure builds to 60+ then it all happens again. On-off-on-off, etc.

When the clutch spins, I am not sure that it means it's engagin or disengaging, so forgive me...

The pressure with the A/C off essentially redlines at about 100 psi.

I want to diagnose the problem. I bought the recharge kit - gauge & Fittings, and three cans for about 35 bucks. If it isn't a recharge situation, I would bring back the kit and spend the money on an obvious repair.

Any ideas?

Are you turning the AC and the fan on MAX when you are testing it?

Yes, the fan is on full blast, and it happens on all dial locations except for the two of them that correspond to the "heat" (i.e. the ones except Max/AC, AC, the defrosters, and another one).

Your low pressure switch needs to be replaced.

Thanks for the info. I will try to locate the switch from a supplier.

Does that mean the system also needs recharging? Or will I not know until the switch is replaced?

I just tried loading my Chiltons CD, but it was so badly scratched it will not work any longer. I searched for threads on switch replacement, but I havent read thru them all yet. If you know of a particular thread, would you mind passing it along?

Thanks again!!!!

Oh, hell yeah!!!!

Changed the part (24.06 + tax from the dealership), refilled with new refrigerant, and it works like a charm!!!

Thanks again!

Just in time for winter!! Sweet!!!

Oh, hell yeah!!!!

Changed the part (24.06 + tax from the dealership), refilled with new refrigerant, and it works like a charm!!!

Thanks again!

Glad to have helped you.

Just remember in the winter to not use Defrost too much seeing it uses the SC system and will kill your fuel economy.