Headlight Level
 

Interesting problem...

Sometimes the LH headlight won't self adjust after the car has been switched on. They drop down, and then back up in normal operation, but more frequently, the passenger side one drops down and doesn't come back up.

It is very annoying. No ranger control errors or anything of that nature, so I am unsure what it is. Is it just a bad motor?

Mike

That's an interesting one, if there's no errors reported could it purely be mechanical inside the headlight?

That's what I was thinking... if the motor is faulty you'd almost certainly see an error.

Might we worth a session with VCDS. Perhaps the output tests might try and cycle the motors and give more insight ?

Interestingly, tonight I got in the A8 after not using it for 5 days, the suspension was in jacking mode as I left it there when I parked it. I turned the car on, the RH headlight went up as usual, the left pointed down. I turned jacking mode off and the front of the car raised.

After this, I restarted the car and both lights levelled correctly. I think the level sensor at the front is playing up.

Mike

OK, I scanned the car, It provided no error messages. I also tested the lights with the VCDS, and they went up and down just fine.

My car sinks at the front when it is parked, and after a few seconds pumps back up again (around 5-8mm) when it is turned on. If the lights are in auto, then sometimes before the car is pumped up, the LH one will come on and point down. If the lights are turned to off, then they usually are fine because the car has levelled before they are switched on.

It's all very strange.

Mike

Ah so you have an issue with the adaptive suspension, that will create problems with headlight levelling as the info comes from the suspension height sensors.

Have you any faults logged for the level sensors or the level system in general like leaks, over temp etc.

If you do have a leak you run the risk of your compressor dieing trying to make up the loss.

No the suspension is fine.

I've had all the struts and compressor replaced last year.

The suspension has always let some air out when the car is locked. I left it in jacking mode for 3 days to check for leaks and there were none. The car moved up and down its travel quickly and works as it should.

Maybe the sensor itself is crappy. One of the first things i did was check the suspension.

Mike

Got you, you mean the self level just as you lock it and walk away, thats normal behaviour.

Still doesn't explain the headlight though?