Electrical Mystery 1970 Merc 230 6cyl - Mercedes-Benz Forum

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post #1 of 4 (permalink) Old 05-06-2016, 11:48 PM Thread Starter
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Question Electrical Mystery 1970 Merc 230 6cyl

Hey guys, new to the forum this is my first post.

I picked up this beautiful old Mercedes from the other side of the country with no papers, it was a thousand bucks and i drove it home without any issues other than a faulty stereo unit. It looks amazing for its age and drives well.

After getting home I got straight into the electrical issues that would be causing the stereo to emit the high pitched squeal whenever its turned on, I suspected an earthing issue as the unit did get quite hot so I cleaned all the connections and replaced the block connector and checked everything was okay...

The result is that the stereo although very crackly and still warm now works and the entire rest of the electrics in the car except the clock have stopped, only they occasionally come back but die again whenever high power is drawn either from turning on the headlights or trying to start, its extremely frustrating to have traded off a perfectly working car for a semi working stereo haha I have wired motorbikes before but for the purpose of shedding light lets assume I am a complete newbie to wiring and the like. Also its worth noting that whenever a battery is connected the negative terminal gets covered in corrosion (see photo), even if cleaned within a fortnight its back.

The car had a complete repaint/rebuild overhaul 6 - 10 years back so most components and wires are reasonably happy, as I said I drove it across the country without any major issues, started first pop every time, very well maintained.

Any help or insight would be appreciated,

I am getting the vibe that I will have to rip most of the interior out and go over every wire in the car but I would rather avoid the many headaches associated with that route.

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post #2 of 4 (permalink) Old 05-07-2016, 04:40 AM
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I would start by removing the stereo.
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post #3 of 4 (permalink) Old 05-07-2016, 06:10 AM
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And replace all the fuses.
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post #4 of 4 (permalink) Old 05-07-2016, 09:23 AM
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She is a beauty!

Also clean the fuse contacts because brass contacts with aluminum fuses will corrode. I sympathize... Last year, my circuit 5 (stereo, clock, etc.) blew a fuse. Somewhere in the main bus, it had grounded. It apparently took several other circuits with it, for when I turned on the lights or engaged the glow plug warmer (it's a diesel), it grounded out. I have one short located to the parking lights on the right side. I guess there should be limited expectation when a car was built in the 70's using cloth-insulated wiring in some areas...

BTW, being a chemistry enthusiast, I've considered electroplating the fuses with copper to avoid the anodizing with the aluminum. But then, I've also threatened to rip out the entire fuse box and putting in modern bayonet style fuses.

Good luck!

Last edited by Cheetahpop; 05-07-2016 at 09:24 AM. Reason: forgot something...
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