jsb357

I picked up a W123 over the weekend an am trying to get it to pass state inspection.

For the most part everything is in order except the high beams.

When I engage them the low beams dim and the FOG lights come on.

I am guessing either the headlight switch or high beam switch is faulty.

Looking for diagnostic tips to determine which it may be.

Thanks

jsb357

Found out a few other details.

Some diagrams I've found show a brown wire to ground off of post 31 on the headlight switch.

I have no such wire.

Also my headlight are the 6 pin Euro instead of the 4 pin US wiring

Would this make a difference in the headlight switch wiring?

jsb357

Removed the ground post and cleaned and replaced

cleaned the fuse connections

Replaced both switches

with no success.

The wiring must be butchered somewhere.

Gonna start in the lights and move towards the dash with a test light, multi meter and a fine toothed comb.

mrmotoguzzi00

Ground was gonna be my first thing to check but you been there... yup time for the multi meter.....

1 tip is used to use was some door bell bell wire... very cheap by the roll, long and stiff, ... good to check a long run... aka completely disconnect switch and light and then use the bell wire to connect direct from switch to the lights... the stiffness helps with being to bend and wrap around stuff with out it hanging everywhere....

jsb357

problem solved

apparently at some point someone took apart the LS (driver in US) head light connector

The high beam and low beam were crossed.

One would think it does not matter but it resulted in the original symptoms.

So $150 in switches for naught.

Live and learn.

mrmotoguzzi00

Yeah now you got some extra switches