Bi Xenon Problem

[Lagotto]

2003 320CLK factory fit Bi Xenons with a high beam fault. Drivers side high beam comes on ok, then after a few seconds reverts to low beam, few seconds more, high beam on again. This contiues to cycle, also the same if holding "flash". I had originaly supected bulb, ignitor or ballast. However, i didnt understand that there was "shutter" which operates the high beam function. This suggests to me that as there is no problem with low beam, the problem must be the operation of the shutter.

Has anyone experienced a shutter problem, if so, could it be the solenoid operating the shutter, is there a fix, looking for ideas, thanks.

 

[LostKiwi]

Could be SAM related. Check power feed to the shutter (and sorry I don't know which wires).

 

[Lagotto]

Could be SAM related. Check power feed to the shutter (and sorry I don't know which wires).

Thanks, yes, the SAM had never even occured to me. My next step will be to remove the front bumper and both headlights. I will then swap the lights side to side and if the faulty light (drivers side) works fine on the other side, that will eliminate the light assembly. Also if the good light (passenger side) displays the shutter fault, I imagine that confirms a faulty signal to the light on that side.

 

[mioba]

Let us know how you get on

 

[Lagotto]

Update, bumper off, headlights out. Cant swap side to side as wiring is different to each headlight, so swapped bulbs again just to rule out, both fine. I then swapped the Ballast, still drivers high beam on/off. Cant swap ignitor as they are inside the light unit, however I dont think there is a problem with ignitor as the low beam stays on without fault. What is happeneing is shutter operates then not, cycles on/off.

That leaves me with a thought that the solenoid operating the shutter could be at fault, the shutter itself moves freely, so need a little help. Im no electrician, but with the headlight out I would like to put 12v to the solenoid to see if it remains actuated all the time 12v is present. I think the small plug inside the housing which has two wires, solid yellow and solid brown are the solenoid. Can anyone confirm this and which is 12v/ground.

I think this is the last thing I can check, then i will have no choice but to get in on a Mercedes Star for diagnosis.

 

[LostKiwi]

Check the signal from the Sam. 5 minutes with an assistant flashing high beam and a multimeter should find which wires go to the shutter. Then check the signal stays high when the high beam is operated. In my experience solenoids tend to work or not work but not work for a few seconds before not working.

 

[Lagotto]

Thanks, I get a bit lost when it comes to electrics, dont even know how to use a multimeter correctly. I can check for DC voltage using +/- probes on the multimeter and thats about it. Do you mean checking for signal at the headlight end where all the connectors meet the sockets? I worry about touching probes to wires in case I cause damage. The two light assemblies are different, the drivers side having 3 connectors, the passenger side 2. Is it likely that the wiring from the drivers side then links across to the passenger side?

 

[Lagotto]

Problem solved. Very strange outcome, might be of help if someone experiences similar problem.

With everything dismantled and after swapping parts side to side, checking signals with multimeter and having someone help watch lights at front while I operated from drivers seat, a fault occurred.

My "helper" suddenly shouted that the drivers side high beam HALOGEN bulb just died. I removed the H7 bulb and sure enough it had blown. I replace the bulb and suddenly not only did this light come back on, but the Bi-Xenon low and high beam light started operating normally again.

I have no idea why this was causing the problem I was experiencing, but have a theory which ive taken from another owner. In another thread, an owner was experiencing some odd lighting problems and one person responded by suggesting he replaced all the bulbs in this light unit as it was a relatively simple and inexpensive thing to do to see if it would make a difference. He mentioned that it is possible for a bulb to be "on its way out, but not yet failed" but still effecting the sensitive electronics in the car.

I believe this may have been what I was experiencing, a faulty bulb, not actaully failed, but was close to failing, creating a problem with the corresponding high beam on the Xenon. What do you think ????

 

[mioba]

I replace halogens as a pair. Older bulbs get weak.