when i bought the 88 back in january the a/c wasnt working, i charged it this summer and the compressor would not work correctly. i went out and bought a brand new denso compressor, accumulator, and the other misc. stuff. the compressor alone was over $500.00. got it all put together, vacumed down and charged, hit the a/c and...........nothing, and then it kicked on twice for about 2 seconds and then nothing. checked its getting 12 volts and ground at the compressor and it wont do anything. it took 2 weeks to get this compressor. everyone i talk to says it should be working if it is getting power and ground. this just sucks. any suggestions? looks like i get to pull it off and wait another 2 weeks or more for another compressor.

 

Do you have an FSM. I have an 88 also and there is a lot more involved. You have a low pressure switch, high pressure switch and that damn resistor on top of the heater/evap box. If any one of these are bad it won't work.
The FSM Electrical Supplement states to check faults under Mode 8 in diagnostic mode. This is on page 8A-66-1. The is for the C68 system.

To operate the Heater and A/C Control Assembly in the Diagnostic Mode, press and hold down the Rear Defog button, then press and release the Blower Manual Up button.
A number from 1 to 9 proceeded by a minus sign will be displayed indicating a particular Diagnostic Mode, the modes available are:
1. Program Number
2. In-Car Thermistor
3. Ambient Correction
4. Blower Number
5. Outside Temerature Thermistor
6. Feedback Pot Position
7. Calculated Door Position
8. System Faults
9. Software Version Number

Advance the Mode Number by pressing the Warmer button. Display the contents of any mode by pressing the Cooler Button.
Select Mode Number 8 and display the contents to determine specific conditions. The contents will be an error number indicating a specific condition as listed in the following
00. Program Number
01. Feedback Potentiomemter-Open
02. Ambient Sensor Open
04. Ambient Sensor Shorted
08. In-Car Sensor Open
16. In-Car Sensor Shorted.

This is just the beginning, there are 12 pages of troubleshooting guides and the diagrams to go with them.

 

thanks, i have the c 60 manual a/c. only 2 pages of throuble shooting. i jumped the compressor off the battery and it kicked in, so i must a switch gone bad or a bad ground. tomarrow i will jump it using the harness ground to see if that does anything. that will at least eliminate if there is a grounding issue.

 

Try jumping the low pressure switch first and see if it cycles. The low pressure switch seems to go out most often.

 

that was it, thanks. now i can be more than just cool driving the vette, i can be cooool too.

 

Glad to help. Good thing it was easiest switch.