Drivers side low beam headlight gone - bulb & fuse ok, what next.

cdb

As the title says, the low beam on the drivers side failed recently.
Replacing both bulbs made no difference. There are separate fuses for the left and right low beams but they are fine, at least an inspection and swapping them around makes no difference - the left low beam works regardless. The electrics that share the same circuit as the lights are all working normally. What would you check for next? The car is an 02 C180.

cdb

Thanks for the suggestion. The connections looked ok, at least there were no obvious signs of corrosion by torchlight last night anyway. That said its probably worth a second look in the daylight.

stek

corroded cables, use a multi meter and check the voltage.

tpotter

Like stek said, it sounds like you are going to need to use a volt meter to find out where the problem is. Or at least, this would be the quickest and easiest way to determine the problem.

Start by checking to see if the light socket is getting current. If it is, then there is a problem between the socket and the light.

Otherwise, if it is not getting power, you would need to follow the line backwards, checking each connection. This will help you pin-point the problem or where the problem starts.

bonzodog2

Maybe the lamps are controlled by relays (so the wires to the stalk and stalk itself can be lower current rating). They often in with the fuses on some cars [edit:not familiar with 02 C180. ], maybe a little plug-in black box about an inch square

cdb

Yeah it makes perfect sense when you think of it like that. I'll grab a multimeter and find out where the problem is. Thanks for the suggestions, much appreciated.

robbie_998

have the wiring checked

Lucifer

You have probably done this but I'll say it just incase. On some cars it is necessary to turn the ignition on and off or even take the key out for the system to reset itself. With this type of system, it runs a tiny voltage through the circuit and monitors the resistance to tell if a bulb is working or not, if it detects a high resistance out of a certain range (ie a bulb gone) it will stop voltage going to that bulb and sometimes even turn another bulb on instead of that one. So sometimes after changing a bulb it will not work until you do this.

nialler

I have the exact problem on the passenger side with my 00 S320 low beam, can't locate which fuse it is and hoping it's not a ballast problem with the unit itself, like yourself replaced both bulbs with high-end osrams and no joy, thinking of removing all fuses from the rear passenger seat unit and giving them a clean but very frustrating, running with front fogs at the moment to get some illumination at night.

N

cian1500ww

Could be a break in the wire either, your multimeter will help you find that.
Check to see if there is continuity from the bulb to the fuse, if there is then that wire is ok and the problem could be from the switch to the fuse.