I took my Vette in today to get the AC system recharged. They checked the system out first and found that the compressor was not turning on.

They checked both pressure switches and had no voltage.

The mechanic then ran 12vdc from the battery directly to the compressor and the clutch engaged.

He said there is a problem in the wiring and mentioned a relay.

I'm guessing the relay on the fact he mentioned it was in the circuit and that it would probably be the easiest to replace. Where exactly is this relay? How hard is it to get to?

Any other ideas as to the problem would be greatly appreciated.

Chances are that your programmer needs to be fixed. It is a black box under the driver's side of the car near the brake pedal.

Remove the box -one bolt, one wiring harness, one bolt for the vacum lines.

Open the box, remove the board and look at the upper right side. You will see two resistors. Is there color change on the on the board? Check the connections. Is the soldier shiny silver or dull gray. If there is any of the above take the unit to a tv repair shop and have the resistors either replaced or resoldiered. Should cost no more than ten dollars- ( the resistors cost .52 in Radio Shack for two).

Thanks Bob, I'll take a look at it tonight.

Any other items I should look at while I start tearing into my car tomorrow? I would like to have a few things to check out while I'm digging in there.

do you have any codes. if the controller is in a failed state, meaning you have an active AC code the compressor will not come on. if you can not pull the codes then remove the neg battery cable for 10 minutes, that will clear all codes. worth a try. it you have a real problem it will still need to be fixed.

I get a blinking LED when I start the car. It's the LED above the OFF button.

How do I pull codes off of the control unit?

don't know how to pull codes with out a scanner, sorry. just disconnect the battery for 10 min. if you still have a problem the codes will come back. if no problem and codes clear then your good to go.
Rich

OK, I had found a code 9, low freon detect. That was the reson for the clutch not engaging.

I did the battery disconnect and that reset the codes. I'll be taking it back in for the recharge tomorrow.

Thanks guys.