Chasing down grounds (W123) - PeachParts Mercedes-Benz Forum

FormulaReed · #1 01-07-2010, 02:37 AM

Hi all,

I have found some really bad wiring in my car (76' euro 300d). Lots of hacked together wires, some shorts etc. The one that is the most troubling is the red wire that goes from the ingnition to the headlight switch. It looks like it's been on fire, the shielding looks burnt to the point that it had fused with some of the sound deading padding that is in the inside of the pannel that coverd it.

I tried to chase down the ground, but I can't figure out where it goes. Is there a grounding strip somwhere in the car? If there is, where is it? The only grounds that I can find are small wires that have been scrwed into the chassie and they are for accessories (like the radio and an alarm that I removed)

Thanks,

Reed

Stevo · #2 01-07-2010, 10:40 AM

You should have a grounding strap from the bell housing to the body, driver side, slide under and have a look see. Weird things happen if this ground is broken.

Jeremy5848 · #3 01-07-2010, 11:07 AM

The body is the "ground strap." There are ground terminals located at key points all over the body. For example, there should be one near the battery, one or two on the left (driver's) side of the inner fender, one or two behind the instrument cluster, one in the lower console next to the shifter, one or two on the left and right sides of the trunk and probably more. All should have brown wires attached to them -- the Germans standardized brown for ground ages ago. As Stevo says, there's a big braided metal ground strap between the chassis and engine. Make sure it is present and making good contact. Remove and clean it to be sure. Access from under the car.