Brake light fuse keeps blowing

darudey · Post by **darudey** » Sun Jul 22, 2012 10:14 pm

Hi all,

My 10amp brake light fuse on my 3 years old 5 door MK7 keeps going. I've blown about 6 of them today.

When I insert it, it's ok for the first minute, it gives you some hope that it works.

1. I just changed the fuse, drove the car for a minute and then pop - fuse gone.
2. I thought I might be unlucky with that fuse, so I tried another, 10 seconds later - pop!
3. I tried checking the brake light bulb, particularly the one brake light I changed a few months ago, gave the connector a little scrub, engine on, brake on, pop
4. So I tried checking the other brake light bulb, engine on, brake on... ooh its looking good.... 1 min later, pop!
5. I tried the middle brake light (on top of the boot), it looks a little tricky to resit the bulb, so I just disconnected it.... new fuse... 1 min... pop!
6. I left the middle brake light disconnected and removed both driver and passenger brake light bulbs. This time I tried a 15amp fuse. Engine on, brake on, 1 min... pop!

So, could it be wiring? Or could it be the brake light switch by the pedal? Theres been absolutely no mods made to the car, its very billy basic, no air con, no cruise control etc.

Please please help!!

mattgibson · Post by **mattgibson** » Mon Jul 23, 2012 10:21 am

Up it to a 20 amp and see what happens.

darudey · Post by **darudey** » Mon Jul 23, 2012 4:50 pm

mattgibson wrote:Up it to a 20 amp and see what happens.

Are you sure that's a good idea?

Blueoval09 · Post by **Blueoval09** » Mon Jul 23, 2012 9:26 pm

Sounds like you may have nipped a wire when you changed the bulb, casing could have worn through enough so every so often when you brake it's shorting out

mattgibson · Post by **mattgibson** » Mon Jul 23, 2012 11:10 pm

when you get xenon's they tell you to up your fuse to 20 amp in the handbook.

darudey · Post by **darudey** » Tue Jul 31, 2012 9:20 am

mattgibson wrote:when you get xenon's they tell you to up your fuse to 20 amp in the handbook.

I was tempted to try this but I'm not using any xenons.

I bought a wire tracer / circuit finder tool for 20 quid to help me diagnose the problem. And I eventually found a blue ground wire exposed by the brake pedal, the black tape around it was torn too. Its not that easy to find, you have to get your head right in the foot well. I guess this wire was rubbing against some metal when I press the pedals - causing the shorts. It probably also explains why the shorts are intermittent. Anyway wrapped this wire up, stuck a 10amp back in, and all is good so far.

Thanks for the replies.

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