Sti blowing fuse..............
Discussion
Sounds like you have a short. Positive wire going to one of the brake lights is earthing out hence the blowing fuse. Could be moisture in there from all the rain we've had, alternatively one of the brake light wires may have got too hot and melted the insulation around the wire so it's now touching the body or another earth wire.
You'll have to get in the boot and trace the wires back. They all go back to connectors under the back seat bottom, and from there into a junction connector under the carpet by the sill close to the B pillar drivers side.
Also check the lightbulb holder make sure it's ok and there are no bare threads of wire touching anywhere they shouldn't be.
HTH
You'll have to get in the boot and trace the wires back. They all go back to connectors under the back seat bottom, and from there into a junction connector under the carpet by the sill close to the B pillar drivers side.
Also check the lightbulb holder make sure it's ok and there are no bare threads of wire touching anywhere they shouldn't be.
HTH
Edited by ScoobieWRX on Friday 31st July 23:39
Thanks for the reply, but the switch was disconnected at the pedal, i.e. the brake lights do not have to be on to blow the fuse. Are they relay controlled, or do they connect directly to the switch? I've had my head in the footwell to see if I can trace the wiring, but as usual the cables just mingle into a huge wiring loom.
Might have to take a "brave pill" and start removing bits of trim etc.
Cheers
Derek
Might have to take a "brave pill" and start removing bits of trim etc.
Cheers
Derek
What year is your car??
Edited to add: Just looked at the wiring diagram for a 2004 STi and there is no relay in the way. Goes straight from the fusebox to the brake light switch and then straight to the brake lights.
Once the switch is disconnected the brake light circuit is isolated from the rest of it therefore it must be a problem from the brake switch power in cable back to the fusebox and thereafter somewhere in the fusebox. Methinks you'll have to trace that back to the fuse box and see if there is a short or melted cable somewhere along there, and perhaps pull the fusebox out to see if there are any shorting wires there.
Dismantle the large flat plastic cover underneath the steering column, it's the one the OBD socket is sitting in and you should see the fuse box. Take a multimeter and set it DC volts as near to 12 as it goes and see if there is a short to earth either power in or power out side of the fuse holder that keeps blowing fuses. Another way is to disconnect the battery and put it on continuity testing to do the same. YOur multimeter may buzz at you if there is continuity.
As far as i can tell Fuse no.16 is specifically for brake lights switch and doesn't service any other equipment therefore the fault should be easy enough to trace.
Edited to add: Just looked at the wiring diagram for a 2004 STi and there is no relay in the way. Goes straight from the fusebox to the brake light switch and then straight to the brake lights.
Once the switch is disconnected the brake light circuit is isolated from the rest of it therefore it must be a problem from the brake switch power in cable back to the fusebox and thereafter somewhere in the fusebox. Methinks you'll have to trace that back to the fuse box and see if there is a short or melted cable somewhere along there, and perhaps pull the fusebox out to see if there are any shorting wires there.
Dismantle the large flat plastic cover underneath the steering column, it's the one the OBD socket is sitting in and you should see the fuse box. Take a multimeter and set it DC volts as near to 12 as it goes and see if there is a short to earth either power in or power out side of the fuse holder that keeps blowing fuses. Another way is to disconnect the battery and put it on continuity testing to do the same. YOur multimeter may buzz at you if there is continuity.
As far as i can tell Fuse no.16 is specifically for brake lights switch and doesn't service any other equipment therefore the fault should be easy enough to trace.
Edited by ScoobieWRX on Saturday 1st August 11:29
derekg500 said:
Cheers.
It's a 1997 model. but looks very similar to what you've just described. I'm off to Goodwood tomorrow, but when I return I'll take a deep breath and dive in there.
Many thanks.
Derek
If you need a workshop manual for your V3 lt me know. I'll pm you a link to the file on my webspace.It's a 1997 model. but looks very similar to what you've just described. I'm off to Goodwood tomorrow, but when I return I'll take a deep breath and dive in there.
Many thanks.
Derek
O.k. guys, finally got to the bottom of it, sort of.
Removed a side piece of dash trim on the drivers side to help trace the wiring, and found a small, red, single pole relay mounted on part of the bulkhead. It looks to be factory fitted rather than after market. Anyway, I unplugged the 3 wires from it and the fault cleared and the brake lights now work. Only snag is I can't find what the relay controls as all seems to be working.
Time will tell I guess.........
Thanks again for the help.
Derek
P.S. Francis, I think a workshop manual is a good idea, any help appreciated.
Removed a side piece of dash trim on the drivers side to help trace the wiring, and found a small, red, single pole relay mounted on part of the bulkhead. It looks to be factory fitted rather than after market. Anyway, I unplugged the 3 wires from it and the fault cleared and the brake lights now work. Only snag is I can't find what the relay controls as all seems to be working.
Time will tell I guess.........
Thanks again for the help.
Derek
P.S. Francis, I think a workshop manual is a good idea, any help appreciated.
Edited by derekg500 on Wednesday 5th August 19:35
Hope this helps.
http://bbs.scoobynet.com/technical-topics-archive-...
http://bbs.scoobynet.com/technical-topics-archive-...
Edited by paul555sti on Thursday 6th August 22:25
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