1991 <NOBR style="FONT-FAMILY: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; COLOR: darkgreen; FONT-SIZE: 100%; FONT-WEIGHT: normal" id=itxt_nobr_0_0>Silverado</NOBR> K1500. 5.7L. Automatic. 4x4.

I'm trying to get A/C working. Here's what I've done and observed so far:

- the blower is fine and all the dash lights appear to be in working order.

- I put refrigerant in the system up to recommended pressure. This was a couple hours ago and gauge shows it's still at the same pressure now, so hopefully this means there's no leaks

- took a test light to the connection at the Evaporator. Lights up when AC button is turned on. Does not light up when AC button is off.

- compressor clutch is not turning. took a test light to the connection at the clutch. It does not light up under any circumstance.

So I'm thinking there's an electrical problem because power is not going to the compressor clutch. Either that it thinks there's not enough refrigerant in the system. Any ideas where I should look?

I'm also thinking it would be useful to test the compressor with a different source of power. Any thoughts on this? Is it a good idea and if so, how should I do it?

thanks

80skeys
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this may sound stupid,but have you checked all ur ac fuses i know my car has 3.took me hours to find that out and when i did everything works fine now

 

I checked the AC fuse that's located in the cab on the driver's side below the steering wheel.

Are there any other fuses or relays I need to check?

 

Locate the low pressure switch and jumper the 2 wire together if it comes on you either need a new switch or the charge is in correct.