Pontiac Repair: 1997 gtp a/c, dual climate, engine computer

Question
compressor wont come on unless i jumper a ground to the relay,then it works fine,freons good.any ideas to start troubleshooting.3800 supercharger,dual climate controls.

Answer
Hi Rich:

Well it can be a bunch of things. either the HVAC control head is not sending the a/c request signal to the engine computer. The engine computer is not allowing the relay to be turned on due to another fault some where. ARe any codes stored in the engine computer? there meay be a code stored that would inhibit a/c compressor control. there could be a wiring issue between the hvac control head and the engine computer or a wiring issue between the engine computer and the compressor relay. That year car had issues with a wire harness rubbing through on the A/C condenser take a look and make sure that the engien harness is not rubbed trough at the A/C condenser. If you have a acatual scan tool and not a "code reader" you can lookto see if the a/c compressor request is present or not. Good luck :)