Check fuses F7, F19 & C4
My a/c has just stopped functioning. Here are my symptoms:
1. The a/c momentary switch light comes on.
2. The compressor doesn't cut in. No cool air from vents.
3. All three fan speeds work fine.
4. The recirculation light comes on (which I think means the switch pack's ok).
5. Fuses F7, F19 & C4 are fine.
6. The connectors into the relay pack on the LHS wheelarch lining are secure.
7. The circuits inside the relay pack on the LHS wheelarch lining look fine (popped it apart to check).
8. I have 12v into F19.
9. I fail to see any voltage into C4 w/ the key in the ignition & turned to position II (didn't try with the engine running, though) - may need to double-check this.
10. The a/c was working fine before I wired up my oil temp gauge which takes power from C2 (piggy-back) - and yes, my wipers still work!
11. Even with the oil temp gauge completely unplugged, still no a/c compressor action.
As I'm a big "what did you touch before it went bang?" kinda guy, how can I be sure what I've fiddled with hasn't caused the a/c issue. I'm also an advocate of something unrelated going bang under coincidental circumstances ;-) I really wish there was a way to diagnose the a/c no worky cause (i.e. low gas) without having to check the gas level!
Also, should the radiator fans come on at half-speed when the a/c is turned on? My rad fans *don't* come on when the a/c button's pressed (and the light's lit) but I'm assuming that the fans are driven by the compressor cutting in & *not* the button pressed.