Electrical Issue 93 300D

[jake12tech]

Working on my 93 300D today and ran into something. I installed the headlights and corner lamps. I have 6V (too low should be 12v?) at the headlight harnesses, but no low beams or high beams. I also have no four way flashers. Or brake lights. I do have corner lamps illuminated however. NO turn signals.

I was reading it could be the combination switch which I am going to replace... Does the combination switch have any affect on the low beams? I have 6v at the harness that attaches to the headlight? Is that enough?

[pimpernell]

Originally Posted by jake12tech

Working on my 93 300D today and ran into something. I installed the headlights and corner lamps. I have 6V (too low should be 12v?) at the headlight harnesses, but no low beams or high beams. I also have no four way flashers. Or brake lights. I do have corner lamps illuminated however. NO turn signals.

I was reading it could be the combination switch which I am going to replace... Does the combination switch have any affect on the low beams? I have 6v at the harness that attaches to the headlight? Is that enough?

Hope this helps, seems that switch does a lot of different things:

1992 300SE Combination Relay problem - Mercedes-Benz Forum

[Diseasel300]

Headlights should be 12V always. The high and low beam are different wattage filaments, both run at 12V.

If you only read 6V, you have a phantom voltage, likely read with a digital meter. Most likely you have a poor ground or a poor connection in a fusebox or relay somewhere. Since you have NO functioning exterior lights, I'd look at grounds or the master headlight switch first since there has to be something common with them all.

[jake12tech]

Originally Posted by Diseasel300

Headlights should be 12V always. The high and low beam are different wattage filaments, both run at 12V.

If you only read 6V, you have a phantom voltage, likely read with a digital meter. Most likely you have a poor ground or a poor connection in a fusebox or relay somewhere. Since you have NO functioning exterior lights, I'd look at grounds or the master headlight switch first since there has to be something common with them all.

Yes, DM told me that. It's a good Craftsman (expensive end one). The fusebox reads 6v for all of them? Am I using the meter wrong?

[ah-kay]

Originally Posted by jake12tech

Yes, DM told me that. It's a good Craftsman (expensive end one). The fusebox reads 6v for all of them? Am I using the meter wrong?

If the car starts and you must have 12V at the fuse box or at the battery. Measure at the battery poles and confirm. 6V will not be able to start the car.

[Rick76]

Where are you grounding your meter?
Do as ah-kay says putting your meter across the 2 battery terminals. If you don't get around 12 volts and the car does start, then you have a problem with your meter. I have seen meters that give incorrect readings with a low meter battery with no low battery indication. Surprisingly one was a cheaper model Fluke which is better than a high end Craftsman, just not as many bells and whistles