8L S3 with a slightly odd Xenon problem

Purple Tom

S3 time...
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Hi,

I've had my S3 for a few months now and am slowly getting it to the point where I'm happy with it. When I first got it, the O/S (drivers side) headlight was pointing at the ground about 8 feet in front of the car, so I plugged in VCDS and could hear the motor working when it was put through the standard output test, but the light itself stayed still. I stripped the bumper off, removed and stripped the headlight and saw that the little clip that attached to the motor output shaft was broken, hence the lack of movement. Fixed that and put it all back together and the headlight was now (finally) pointing in the same direction as the N/S light - happy days!

Along with that I replaced the broken rear axle Xenon sensor and checked the outputs of both front and rear sensors (all OK) then took it for an MOT and adjusted it properly using the light meter (when in adjustment mode on VCDS).

Ever since then, when driving with the headlights on, the O/S light will suddenly and randomly just adjust itself to its lowest setting and point at the floor in front of the car. If I cycle the ignition off and back on again it will then pick itself back up and point in the correct direction again, until the headlights get some form of input in terms of either a change to main beam or switching them off and on again, at which it will go back down again.

I can't figure out why - can anyone help??

What I've done:

Checked the height adjustment sensors - all good and producing the correct voltage (plus you'd think if there was an issue here then it would affect both headlights?)
Adjusted both headlights when in VCDS adjustment mode - all good
Carried out output tests and checked that both lights go up and down at the same time - they do

As far as I can see, all is good. If anyone could help or offer some advice I'd be grateful!

Thanks
Tom
 
It's the xenon level sensors that's adjusting the light. Do another adjustment with the lights off btw. And make sure the ground is level.
 
Broken wire possibly, giving intermittent engagement.