Hi

I have a V40 (2000) 2.0

recently the headlights have exhibited issues. Firstly the lamp connectors were frail having melted and degnerated over the years. I replaced those. Now more recently I replaced bulbs and now am finding that the front right headlight does not work. The sidelight and high beam work fine.

I have traced the wires and it appears that the feed to the headlight comes from an ECM (electronic control module) located under the panel by the drivers right knee. The part number is 30859700.

If I connect a live cable to the wire which goes to the headlamp then the lamp lights up. the wire which brings power for the right headlamp comes directly from the fuse box and that is live. There are four bubdles of cables plugging into to ECM and I would like to be sure that the switching mechanism for the ECM relay is ok before getting a replacement ECM. They are very expensive as a new part.

Can anyone help? Is the ECM module a common fault?

Yes your cem (the electronic box) may well be at fault, replaced a few for this.

If it was my car though I would not be replacing this unit to fix this fault as expensive. A cheaper option (and safe) is to wire a relay in, triggered by the good cem headlamp output. This would require you to find a good power source for the relay of the ignition wiring. DO NOT be tempted just to join the headlamp feed wires together thus eliminating the need for the relay as you will simply overload the other internal relay in the cem and then a new cem would be the only option.

Hello

Thanks for your reply. I will consider doing that if I can't get hold of a second hand unit.

Last night I took the unit out of the car and opened it. through a process of deduction I worked out what I believed to be the relay unit which is still functioning (left headlamp). Then I tried lightly tapping the neighbouring relay unit with the rubberised end of my screwdriver and hey presto - headlamp is back on !

I appreciate that this is a a rather unorthodox repair technique but it seems to work for the time being. I expect it will fail again and I will back to where I was.

I would be happy to try replacing the relay unit on the pcb if I could get my hands on another. Does anyone out there have a CEM exhibiting a fault and about to throw it away?