Daytime Running Light Out
 

Hello everyone;

New member, and new to Mercedes-Benz. I just bought a 1997 Mercedes E420, with 94,000 KMs. In fantastic condition, without any rust or corrosion - the only issue is the one daytime running light doesn't work.

The guy I bought it from took it to his mechanic to be certified and E-tested, and passed all except for the safety, which only failed due to the one daytime running light being out. They replaced the bulb, but it didn't solve the problem. When you switch on the full evening lights, both daytime running lights work.

Would anyone have an idea of what could be the problem with it? I'm a DIYer and would prefer to do the work myself if possible.

Thanks for your time!!!

what I am understanding:

you turn the headlight switch 1 click clockwise and only one of the two "city"
lights (inside the inner headlight assembly and below the H7 high beam bulb)
turn on, however....

if you turn the headlight switch to the 2nd click clockwise, which turns on the
low beam, both city lights turn on.

you've also reported that the bulb which was not lighting up via 1 click of the
switch was replaced with a new bulb, it did not resolve the problem

if this is accurate, voltage is not passed through to the bulb under switch
click 1, but does so under switch click 2. (you can verify this using a DVM )

the conclusion I am drawing is that the headlight switch is bad (which is not
uncommon with the w210 models).


natch, this diagnosis is limited to the failings of keyboard troubleshooting

Thanks Raymond G- I'll give that a try!!! I'll let you know if that works. Thank you!