Speed humps, indicator stalks and fuses blowing

[9oneone_newbie]

Hi, as a new 1982 911 SC owner - I need some assistance with an electrical fault please. I have blown the indicator/turn signal fuse about 4 times when I go over a speed hump or a road that isn’t smooth. I tried to isolate the problem and have failed. The headlights, hazard lights all still work and the high low beam activated by the indicator stalk still work. Anyone have any ideas? Thanks in advance.

[brianlay]

Which fuse exactly?
You’ve probably got a wire with worn insulation and it shorts to the chassis when you go over a bump

[9oneone_newbie]

Originally Posted by brianlay

Which fuse exactly?
You’ve probably got a wire with worn insulation and it shorts to the chassis when you go over a bump

16A fuse that powers the flasher relay, brake lights and backup lights. Is the easiest solution to then trace all the wiring between the relay and the indicator stalk and make sure it is all insulated? The short doesn’t happen when I use the indicator stalk, depress the brake or reverse. Could it also be the flasher relay needs replacing?

[brianlay]

Assuming you're referring to Fuse 16?

That fuse feeds the back-up lights and flasher relay, but not the brake lights from what I can see.

You do have a wiring diagram?

The turn signals have their fusing for each side downstream of the flasher so the problem must be in the flasher wiring or turn signal stalk.

I doubt that the problem is in the flasher itself, since it's working.

Any signs of non-stock wiring near the fuses, or under the dash?

[bkreigsr]

Sometimes aftermarket stereo installers use a power source wherever the opportunity presents itself. On my car, they used the red wire on the light switch, and every time I hit a pothole the fuse would blow.
Check to see if there is any metal to metal contact at the terminals possible where the big red wires are attached under the dash.
Bill K

[9oneone_newbie]

Thanks for all the help. Ended up having to take it to a Porsche mechanic and turned out that the reverse/backup lights were the cause and seemed to have been grounding against the frame when the car went over a bump. Waiting for spare parts at the moment. My
Next project is to rewire the whole car..maybe a year away from that given how shoddy the current wiring is. Thanks all for your help

Below is a pic of my 1982 Porsche 911sc. Smiles every day that I drive it

[brianlay]

that was my first guess...glad you found it!