A friend og mine has a Vauxhall Corsa which has sat for 2 months doing nothing. Now it keeps blowing headlamp and indicator fuses. They last 2 minutes before they give up.

I've checked the obvious:

1. Fuse ratings
2. Dodgy wiring
3. Any earthing at the bulbs / bulb holder

Ideas?

Probably not useful but my friend had a knackered Ford Capri once and had problems with the fuses blowing.
He left it outside so long that some mice decided to live in the engine bay and nibble on the wiring. Turns out they'd eaten through one of the cables and it was shorting to the chassis. I think his solution was to get rid of the mice and just wrap the wire with some electrical tape...

- Trevor

They last 2 minutes before they give up.


It isn't likely that the car is equipped with Lucas electrical components, because the fuses do last for two minutes instead of failing immediately.

Q: Why do Englishmen drink warm beer?

A: Lucas refrigerators.


Anyway... the only reason a fuse will blow is because the circuit the fuse is protecting is drawing more power than the fuse can deliver. If the output device itself (headlamp, indicator) is not defective, then the only remaining possibility is a shunt to ground in the wiring between the fuse and the device.

Unplug the connectors at the headlamps, remove the fuse, then put a meter between the output side of the fuseholder and ground and you will see you have continuity where you should have an open circuit.

tanstaafl.

I think the divide-and-conquor rules apply here, in other words, rather than suspect all of the car's electrics you should disconnect/isolate large portions until the problem goes away and start homing-in.

Here's a few suggestions, some based upon Vauxhall experience:

I think the front to rear wiring has a connector in the NS footwell side kick panel. Disconnecting this _should_ stop the rear lamps working and therefore eliminate the rear wiring.

One common indicator/headlamp connection area is the steering column stalk controls - maybe something's up there?

Usually in the fuse area there are relays: You should have headlamp (or at least a hi/lo beam) relay and an indicator relay - unplugging one of these might help narrow the cause.

Sometimes (I think) the hazard lamps work from a separate relay, although the wiring is common to the lamps removing the hazard relay might give you a clue.

Re-reading this I'm mindful that I've assumed that you need to operate the headlamps/indicators for the fuses to blow, is that actually true? Maybe you could elaborate a little on what you have to do to get the fuses to blow?