Brake light blowing fuse

[Silver 911]

Happy New year all...
As the new year comes in, I am having my first new year problem! My brake lights keep blowing their fuse? Any body have a suggestion?
'85 911

[cstreit]

Almost certainly has to be a short. When you hit the brake, the power to the brake light bulb is shorting to ground before it hits the light itself. Trace the wire from the switch back to the brake light housing. Look for fraying and expecially where the wire routes over/under/through a metal area.

[RoninLB]

I usually assume in a reply that the questionare guy always goes thru the basics.. like bulb sockets, etc.. it's not always the correct reply, but that's my problem..
so I'm w/Chris on this one, generally speaking.. and if I lose patience searching for the short I'd get one of those "Short Finder" gizmos.. that cost about $25.. one part goes into the fuse location and the other part is held close to the wires and gets triggered when close to the short..
sometimes German electrics is a PIA.. like the fuse buss causing problems. so I keep reminding myself that I'm working on a museum..................Ron

[JDaniel]

Make sure you check the wiring for the third brake light. This can be pinched/frayed and has caused several people to keep blowing brake light fuses.

[Eagle Keeper]

I had the same problem with my reverse lights. It turned out one of the wire terminals worked its way loose and was contacting the metal back to the brake light housing. It might be worth looking at before you spend a bunch of money on fuses!!!

[Adam]

Do you find that the corresponding front park-light has problems too? They run on the same fuse (at least they do in my old 2.7, I haven't looked at the Carrera).

My '76 had a similar problem after re-assembly from the Panel-Shop, but my front park-light (same side) kept blowing the same fuse. I pulled the front headlight to find the park-lamp incorrectly wired. I swapped the terminals and then re-sprung the rear brakelight (on the same side) terminals. Solved the problem!

Hope yours is as easy as mine was.

[Early_S_Man]

Art,

If you disconnect the 6-pole bulkhead connector on each side of the body for each hamp housing ... you can test for shorts on each side. Sometimes the housings collect ater and mud ... and shorts develop at the back of the sockets. After disconnecting, it is very easy to remove the housings from the car, and clean up years of mud and dirt inside the lamp housings and within the wiring harness. Sometimes the rubber drain fittings get clogged, too, and need to be cleaned or replaced!

[Silver 911]

Thanks guys...I just finished-up snooping around and may have found the problem or a potential problem! It is hard to trace the wiring, since I am a new Porsche owner and I am a litte reluctant to start pulling things apart (I have to buy the Bently service manuel). Behind the passager side rear well were two wires that looked like they been rubbed by the wheel and the copper wiring were exposed...and since this is the first time the car has been in the rain, since I owned it ....I am hoping this was it...taped it up and hope it holds. Now my question is - do these two wires have anything to do with the brake lights???? Also my brake lights and cruise control are on the same fuse...crusie control is not working on car.

[makaio]

I think the wires you described, are the ones used for a European rear foglight. I could be wrong though.

[Silver 911]

Car is US spec'd...no rear fog lights

[makaio]

I understand. But my US spec SC has a similar/same wire, and it is for a rear fog light. Or so I have been told.

[bigchillcar]

Car is US spec'd...no rear fog lights

I think they all were manufactured with the wiring for those lights even if they weren't installed on the car in the U.S. My U.S. '74 has them for example...
Ryan

[Silver 911]

Come on guys..... can't anybody give me a definite answer??? The two wires coming out of passenger side wheel well and going towards the rear are for...........?

help!

[RoninLB]

Originally posted by Silver 911
The two wires coming out of passenger side wheel well and going towards the rear are for...........?

help!

if they end at the oil tank, then ___ ______..................Ron

[Silver 911]

oil tank...rear fog lights...brake lights....now I am confused!

[RoninLB]

Originally posted by Silver 911
oil tank...

Sorry Art.. there are 2 wires that go to the oil tank.. they can be easily seen.. they are for the oil tank level sender.. they are vulnerable to road debris, and the wire connections vulnerable to corrosion................Ron