V8 Stingray

Hi Guys,

Just purchased a new '89 Vert and the previous owner stated the A/C had stopped working in the car. When turning on the A/C in the car, the A/C Compressor Clutch would not engage, so initially I thought it was the coil. Just to be sure I tested it further by providing power to the coil and the clutch engaged driving the compressor.

Any idea as to what to check next? Fuses all look fine, I was going to check the connectors at the back of the A/C control unit in the dash, but can anyone point me in the right direction of anything else to check?

PatternDayTrader

Yeah step one is check and be sure its full of refrigerant.

V8 Stingray

Ah... so am I right in thinking that if everything was working ok on the electrical front, the clutch might not kick in due to the low pressure switch?

I was expecting that once I turned on the A/C at the control panel the compressor clutch would kick in, regardless if it had enough refrigerant or not.

billschroeder5842

Yes, you have the theory down. Run the diagnostics and see what you car is telling you: Look for an 09 as that means low freon

PatternDayTrader

Yep, you are correct.
The clutch will not engage unless there is sufficient pressure in the system.
The refrigerant is what moves the oil through the system, the oil that lubricates the compressor. So insufficient refrigerant means insufficient lubrication. Anyway, there is a pressure switch the prevents the compressor from running. The low pressure switch. Don't worry about how you jumpered power to the clutch for testing reasons though, unless you drove it around that way then it didn't hurt anything.

Churchkey

89 - the AC low pressure switch is in the suction line (the large aluminum line) in front of the evaporator case. Un plug the E connector & jumper the terminals in the E connector the compressor should run, if so the system is low on Freon. Remove the jumper wire have the system charged & leak tested.