I have the oil pressure and temp VDO guages. When I turn the a/c on, they spike. I found and fixed two shorts after I bought the car, but I may have more. Before I fixed the shorts, the lights worked in the guages, but now they don't. They seem old, but can they be blown? I know I need to take the time to follow all the wires to look for more shorts; but can anyone give me another cause for my problems? Thank you.