Any ideas? I can't see an obvious short, and despite having studied electronics (to an extent) I can't think of anything else that would cause this failure. It seems to be a standard wattage bulb.

Any thoughts?

cheers

James

Does the fuse cover high beams? Other than that, listen if the relay is arcing more than usual

Yeh i was going to say switch the relay.
Cheers Adam

Same fuse...I think it is....why? You sound like you have a cunning plan hatching

Relay...interesting thought...I'll pull a spare at the scrappers tomorrow. I'm guessing it's in the fusebox? (Will check tomorrow).

It blew after they had been on for about 10 seconds, suggesting mild continuous overcurrent to me. I might pull a couple of spare H4 bulbs too, just in case some cheeky tyke has dropped a 100w set in there.

cheers

James