ground wires to instruments

[Joe]

I'm sorting through the dash of a 230SL I bought last year, and am wondering if there are separate ground wires to the tach, speedo, clock and center gages. The previous owner sort of put things together the way he wanted, with no knowledge of what is right.
Thanks,
Joe

[waqas]

There are definitely separate ground wires to each of the speedo and tach, but not sure about the center cluster (I think that ground is part of the harness that attaches behind the center cluster).

The ground cables attach via the knurled nut that tightens the rear holding clamp on each instrument.

[graphic66]

And they are brown.

[Joe]

Thanks, guys. Does the clock also have a ground wire?
Joe

[egggplant]

quote:Originally posted by waqas

The ground cables attach via the knurled nut that tightens the rear holding clamp on each instrument.

This is a common grounding method that I've seen on many cars of the period such as Volvo, Alfa Romeo, etc.

[waqas]

quote:Originally posted by Joe

Thanks, guys. Does the clock also have a ground wire?
Joe

If I remember correctly, the clock has a little wiring harness connector that should contain the ground wire as well.

[ja17]

Hello,
 Only the tach (rpm gauge) and the speedometer have the separate brown ground wire with the ring terminal which attaches under the knurled thumb screw. The center gauge and the clock are grounded through their wiring harness and plug arrangement.