Help! Rear fog lamp fuse keeps blowing - MOT tomorrow

[TUS 2 CON]

Hi - hoping someone can help.

I've got an MOT booked for tomorrow and thought I would give the car a quick once over this evening to check everything is ok. 3 hours later and I'm fed up.

Basically I noticed the rear fog wasn't working. Tracked it down to blown fuse. However when I replaced the fuse again it blew instantly. My fuse diagram says the the fog light, boot light, boot solenoid, stereo and interior light are all on the same fuse. So I have disconnected the interior and boot lights, the boot solenoid the head unit for the stereo and another bit of it that goes under the centre consel. Fuse still blws everytime, the moment I put it in.

Any ideas???

[Djdan]

Do you want to mend it properly or pass the test? If its only for a blip id be tempted to do something dodgy (al be in on hand with a fire extinguisher) Any shorts if u measure the resistance across the bulb terminals?

[TUS 2 CON]

Would be happy to bode it for the mot and the get it sorted at my service in a months time. What do you suggest?

I haven't checked the resistance - I'm not that technical and I wouldn't know what I'm looking for

[Djdan]

A bodge would be put in a bigger fuse, see if it still blows, worst case replace it with wire. Obviously this is only to allow a 2 sec check. Fuses blow when a current above the rated value passes through them. This is usually caused by a "short circuit" where the positive and negative terminals of the battery are joined and causes a very large current to go down the wire. If the 2 lamp holder connections (with the lamp out) have a very low resitance ie anything close ot 0 ohmns, i wouldnt bodge it as it could very quickly catch fire. if its infinatly high reading your circuit is fine but your lamp is drawing more current than the fuse can provide. It could however be a multiude of other things! Upto you! Personally id disconnect it, take a feed from the cig lighter and wire the light to that and just fire it in when he asks for fogs

[glow worm]

Cig lighter is on the same fuse number 11 20Amp.

Edited by glow worm on Wednesday 23 October 08:27

[nawarne]

glow worm said:

Cig lighter is on the same fuse number 11 20Amp.

Edited by glow worm on Wednesday 23 October 08:27

...And therefore, I would check the cig lighter socket for something metallic dropped in it (my daughter's A3 was popping this fuse - IIRC an earing stud had fallen in). Also check the wiring under the socket for a short circuit.

I wouldn't suggest increasing the fuse capacity - but might be worth giving the fuse board a spray with contact cleaner, before inserting another fuse.
Nick