Headlight moving on it's own

[ajcommercial]

Hiya all.. In these barmy sunny Summer days the use of headlamp is greatly reduced compared to winter but I was in a tunnel the other day and noticed the reflection on the rear of the car in front that the O/S headlamp was going up and down on it's own..  Would this be caused by a faulty headlight aim adjuster switch ? Or something else ??

[mikeB]

I had a similar problem with a Mark 3 Ford Mondeo. I know it's an entirely different car but I suspect the mechanism is similar. The adjustment system works on a Wheatstone Bridge principle where the dashboard control sets a certain resistance and the matching device in the headlight unit responds to match the resistance. This results in the headlight unit motor moving up or down, thereby adjusting the headlight beam up or down.

The fault could be in any of the dashboard control, the wiring, or the headlight motor. I would start with the headlight motor as it has most work to do and is in a hostile place, exposed to cold, weather etc. For my Mondeo the motor cost (wait for it) just short of £100 from the dealer (who apologised that they were so expensive). Needless to say I didn't buy one from the dealer. I got 2 motors from a scrapyard for £10 and the one I fitted continued working until I sold the car. Mine was very easy to fit.

[ajcommercial]

Hiya MikeB.. I agree with your estimations but I think the headlamp motor is part of the headlamp inside the housing so a new headlamp is the only answer, I could be wrong though.. I have changed the level switch as it was a 2 min job and I had a second hand spare so I am just giving that a test just now, next is headlamp but it is a bit of a job so hopefully it's just the level switch..