Wierd Headlamp problem - Offside headlamp is delayed coming

[SteveSmith]

Hi all,
I'm new to the Mercedes camp so please be gentle
I have just bought myself an '88 (F) 300CE which I'm pretty pleased with ... but it has a strange fault that I can't seem to figure out.
When driving at night in the lanes I often use high beam but when I go back to dipped, the driver side dipped beam takes a few seconds to come back on. The lamp fault light comes on during this outage but goes out again when the dipped light comes back on.
I've wiggled wires, swapped bulbs over etc to no avail. It'd be nice to get this working correctly ... any thoughts?

 

[Arnie]

Wierd Headlamp problem

The changeover from high to low beam may be operated by a relay and this may be sticking.

You'd need to check a circuit diagram

It might also be that you have a broken fillament attacment point on the lamp, but then its operation might be more intermittent.

 

[SteveSmith]

Wierd Headlamp problem

Cheers Arnie,
I swapped the bulbs over to prove whether it was something like a filament but the problem stays on the driver side.
I've been over to Halfords for a Haynes manual to see what the wiring looks like but they dont have one, just 190s ho hum.
Can anyone suggest what wiring there is and if there is a relay?

 

[Spike]

Wierd Headlamp problem

I have a manual at home for the 124CE so I will have a look at it 2nite and let you know.

FWIW, I too suspect it to be a problem with a relay. Its the only possible thing in the circuit that acts in a mechanical fashion ....the symptoms you describe appear to relate to a mechanical component.

 

[SteveSmith]

Wierd Headlamp problem

Nice one Spike, thanks for that.
I just ordered the Haynes W124 book from the club book store.
I'm guessing that W124 is a generic model/year range which includes my 300CE?
Once I know which relay and where they live I'll be laughing I'm sure.
Thanks again
Steve

 

[Spike]

Wierd Headlamp problem

unfortunately the manual isnt very intuitive. The best I can glean from it is that the wiring goes from the switch to something called a 'light control unit' and then on to the bulbs.

It does not say where this unit is or indeed what it does. I suspect that this is some kind of glorified relay but cannot be sure.

One thing - When you use the flasher rather than the hi-beam switch does it still display the same symptoms?

 

[Spike]

Wierd Headlamp problem

CGI timeout double post *Again* Please ignore.

(Edited by Spike at 11:51 am on Oct. 26, 2002)

 

[SteveSmith]

Wierd Headlamp problem

Hi Sp!ke,
Sorry about the delay in getting back, no tizzy till this afternoon
It only does it when I've been on high beam and come off it, not when I just use the flasher (dirty mac on front seat ready for every oppurtunity).
Strangely, it hasn't done it for the last few days ... fingers crossed