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Electrical gremlins

Posted: 18 Nov 2018 02:12
by Nustad 510
Hi all,

I have a '71 510. Four door, RHD. With the ignition on all indicators work normally. When I turn on the headlights, the fender indicators partially illuminate. I also noted the speedo cable at the rear of the instrument cluster gets warm. Headlights switch between parkers, Low and High beam normally. Also the temperature gauge is now erratic when the engine is running. All fuses are intact. Fuse box has been in a vinegar bath. All harness connectors were cleaned with electrical contact cleaner and a toothbrush. Has anyone experienced this problem. Its got me stumped. Any help would be appreciated.

Cheers, Shaun.

Re: Electrical gremlins

Posted: 29 Nov 2018 11:18
by yenpit
When a metal "wire" like a speedo cable or a choke cable get hot, it's usually an indication of a GROUND issue.............exactly where is tough to pin point! Do you have a good SOLID ground strap/cable on the engine/trans?

Re: Electrical gremlins

Posted: 29 Nov 2018 19:30
by Nustad 510
Thanks for the reply Yenpit.

Further testing led me to also think it was an earth issue. I do NOT have a ground strap. :oops: Only the Negative battery cable to the engine block. I will definitely try adding one.

Re: Electrical gremlins

Posted: 01 Dec 2018 01:14
by Nustad 510
Hi all,

I'm pleased to say the problem is fixed. :D I ran a cable from the negative battery terminal to the body work (captive nut on the strut tower). This has provided a decent earth and now everything functions correctly. Thinking back my previous 510 had this exact setup. Somehow I didn't notice it missing on this car.

Thanks very much for your help, Cheers
Shaun.

Re: Electrical gremlins

Posted: 12 Dec 2018 07:14
by Edm620
Whenever there is any kind of electrical gremlin, 99% of the time it is caused by a bad ground. Glad you found where yours was!