Rear Lights failure Electrical help
 

Hello,

Here is my next challenge to sort out, the lights. I know all the light on this car have worked when I first bought the car. Now the following rear lights will not go on. License plate lights/markers (both sides #9) and right tail light (#12) cops keep pulling me over on this one :( (they finally got me protect and serve, what a joke)
Also my instrument cluster lights, Shifting lights, and climate control lights do not work

I took the connector apart under the drivers side and measured the wires in power and ohms I also wire brushed all of the connectors where I took my readings from.

The female connector (going to light switch/fuse box) (light switch turn 2 clicks to the right)
Volt DC (200)/200ohms/2000ohms
1 12
3 12
5 .01/40.5/48
7 0/40.7/74
9 0/26.7/72
4 5.9-6.03
6 0
8 1.97
10 12
12 0/27/48
14 0/0/545

Female connector all power switches off
200ohms/2000ohms
1
3 7.4/7
5 1.4/1
7 1.3/1
9 3.8/3
4 55.3/55
6 (nothing registered) (reverse was not engaged)
8 0/642
10 3.8/3
12 3.7/3
14 0/542

Male Connector (going to lights)
200ohms/2000ohms
1 (nothing registered)
3 (nothing registered)
5 9.3/4
7 9.1/4
9 8.7/4
4 45.5/39
6 7.8/2
8 7.5/2
10 8.4/3
12 (nothing registered)
14 9.4/2

Colors of the wires
1 Assuming some sort of power wire
3 no sign of blue wire in trunk area
5 Left Turn Signal
7 Right Turn Signal
9 Side Markers, License plate light
4 no sign of blue/black wire in trunk area
6 Reverse/back up Lights
8 Brake Lights
10 Left Driving light
12 Right Driving Light
14 Ground I assume


If anyone could lend some assistance on this one It would be much appreciated.

I don't why you have all this data for. What you need is an electricl diagram and trace voltages. Also make sure you have a good ground, low resistance to ground, at bulb. (usually bown) If you are new at electrical stuff start thinking of electricity as plumbing. "Voltage is same as Pressure"; like in a water hose.

I think you are making it way too complicated.

A basic electrical circuit (ALL) Pressure start at + on battery. This Voltage then is routed to any any load. In your case a filament for light bulbs. This voltage pressure will not go THRU the load unless the is a Ground on other side of LOAD, Filament.

The ground side of the load is routed back to the the - side of the battery.

Most instances the ground is not the problem, but can be.

We need the model and year, in order to come up with a diagram that will help sort this out.

Add it to my signature as well
1980 Mercedes Benz 300SD Turbo Diesel

I have removed and cleaned Five grounds. 1 in engine, 2 under instrument cluster, and 2 in the back under the rear seat left and right. I was unable to reach he one under the passenger side as the blower is blocking access. It appeared shiny and did not move when I tugged on the wires

I'd start by replacing all the fuses. The can develop cracks, and corrode over time.


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Ditto, check the fuses. On the W126 diagram, it is F1 and F3 (the W116 may be the same) and the fuse is electrically between the light switch and the lights you mentioned.

To keep from having intermittent problems, ensure that you use copper fuses (not aluminum).

I have cleaned out the fuse box, and made the surface contacts nice and shinny again, all the fuses are brand new coppers.

Also my instrument cluster lights, Shifting lights, and climate control lights do not work (added to first post)

Managed to resolve the issue by moving the wires on the light switch to a terminal that had power, I believe the light switch is finally biting the dust. I still need to work on the right taillight though currently soldered another wire to it, so the cops would stop harassing me. All my beautiful lights work once again though!