1991 Silverado k1500.

The blower works fine to bring in outside air, but when I press the AC button the compressor clutch does not engage.

• The AC fuse located inside the cab near the driver is okay

I jumpered the low pressure cut-off switch on the accumulator: but still the clutch does not engage

What's the next thing to look at?

- 80skeys

 

Check the wire for power going to the A/C to see if it is gettin a signal.

 

It sounds like if you have power, just remove it and take it to autozone and have them test it.

 

I checked it. No juice.

 

Now that I know there's no power to the compressor, where do I look next?

 

Ok next locate the relay for it. Most systems have a fuse and a relay for the A/C. Only way for a quick check is to replace it wit a new one.

 

Also check to see if there is power to one side of the low pressure switch.
I have replaced quite a few of those control heads too. Usually they will flash when there is an issue.

 

There is no power to the low pressure switch. The control head is not flashing.

I have no idea where the relay is on this truck. Anybody know?

 

I think its behind your glove compartment.

 

It looks like there are three identical relays in a row from left to right, behind the glove compartment. None of them are labeled as to their function. Anyone know which one is for the A/C?