I need some advice! I have a 99MY classic UK Turbo estate without air con. All was well until last week when for some reason the fuse for my internal fan and heated rear window keeps blowing. Its a 15 amp fuse and blows with no load on the fan or heater element. When you turn on the ignition the fuse blows. The annoying thing being that sometimes it doesn't do it, but a fuse doesn't last more than a couple of days at the most.

Any ideas? A friend of mine who is an auto spark says that there is a short but it has so far not been traced.
Any common faults or ideas would be greatfully received.

David

 

I assume you've checked, and that only the two things you mention are on that fuse?

OK, so if it's blowing with no load, the items are probably OK, and the short must be inbetween the fuse and the switch?

Try to isolate which circuit it's on, see if you can remove one of the circuits from behind the fuse, then check if the fuse still blows. Better than looking in two places at once.

If circuits can't be easily unplugged, cut the wire that has the most play, it can be soldered up again and a bit of heatshrink applied once you're done.

It'll not be easy to find, you will probably need to ask on here if anyone has a wiring diagram to help. I had to find a dead short on a Xantia, took me three days!

Alcazar

 

Are you sure you've got the right amp fuse in that socket?

Also for any of the wires that supply power to the heater matrix have you cut into them for gauges or displays etc.. I blew two fuses in quick succession the other night for my dash lights whilst fitting gauges.

If you have cut into them make sure there is not short as mentioned ealier

You could aslo use a multimeter to check continuity for the supplied wires for that fuse.

 

Thanks for your advice.... keeping sending as much as you have. I am puzzled and agree that its definately a problem with the feed or even a short as it's a standard car without any choping into the loom and the fuse is correct. It ran well last week for a few hours with a 10 amp (5 below recommended) fuse in and then a couple of days ago blew a 20 amp fuse to bits on a flick of the key!
I'll get my mate back with his multimeter and ask him to start tracing feeds.
I noticed that there is a relay up at the back of the dash. Is that anything to do with the heater fan / heated rear window?
Thanks again.

Regards,

David.

 

Which fuse? On an MY99 UK car the rear window defogger has its own 20A fuse no.22 in the fusebox in the engine bay. The heater fan fuse(s) are 1 and/or 2 in the fusebox behind the coin tray and are 15A.
Kevin

 

Its the third from the right on the bottom row behind the coin tray. It has the words Air Con on the back of the coin tray. Its a 15 amp fuse. My car doesn't have air con so I presume that this fuse controls the internal fan and the heated rear window as both of those items don't work when the fuse has blown.

 

Problem Solved!!!!!

The fuse in question is for air con which my car doesn't have. The reason that it kept blowing was owing to the loose wire shorting out in engine bay, that in air con cars is attached to the aircon pump. Once it was tucked out of the way and insulated then problem solved. The reason that the blower wasn't working is because that fuse is the live feed to the blower motor relay under the dash, so when you turn on the aircon the feed provides power to the blower motor..

Thanks for those of you that took the trouble to reply.

Regards,

David...