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Hi, my full beam switches itself on at random when car is not in use, draining the battery. As soon as you turn lights on the problem seems to vanish, I think its something to do with the dim/dip. checked all relays, they seem to be fine. I'm wondering if its the logic module DAC 6902 but its sealed & an expensive replacement if i'm not sure its the cause. Any ideas guys ?

AFAIR, one version of the XJS suffers from overheating contacts in the fuse box, leading to distortion and potential shorts or (more usually) open circuits. Unlikely to the case, but worth checking the fuse holders associated with the headlights for signs of damage, arcing, burning and so forth.

Apparently the problem with the logic module is that the solder contacts deteriorate. You could try opening it and examining the state of the solder tracks, which could then be reflowed as necessary.

Good luck

Paul

Thanks, I think I'll take a chance & order a module

Hi - we did an article on repairing the headlight logic module in the January magazine that may be worth a look