On my '00 XJ 4.0 AW4, the engine RPM kept surging up when at idle. I determined that the AC compressor was cycling on and off no matter which position the HVAC system was set to ( I know the AC comes on when in defrost mode). This happened at approximately 45 second intervals. I pulled the AC relay and the compressor no longer cycles (and my AC obviously doesn't work). Do I just need a new relay or is it something bigger?
Carl