As the car has not been used for 12+ years, as you might expect for a car in the UK, the headlight pop-up mechanism didn’t work. First of all, I had to source the double-sized relay that was missing from the car. When I put that on, the pop-up mechanism started to move, but was struggling. So, I immediately stopped.

By using the manual wheel on the motor, it was clear that the bar/bearings were corroded. So, I removed the bar and the end pieces, cleaned off the rust, gave them a lick of paint and reassembled. The pop-up mechanism now moves very nicely.



The issue I now have is that the lights don’t come on – using the multi-meter I can see that there is no current to the bulbs (but the brown earth is OK).

I did a test I have seen on Rennlist where I removed the relay and jumped (with a fused lead) between two pins in the CE panel. Immediately the main beam light came up on the dashboard and there was current at the bulb connectors.



I have opened up the relay, given it a spray of connection cleaner. I can see 3 of the 4 relays working as I:

• Turn the headlight switch, and the relay initiates the pop-up (front, left switch in relay)
• Turn on dipped and main beam (back left and back right switch in relay).

The only switch in the relay I cannot see moving is front right.



I have seen a reference on Rennlist to an issue in the headlight motor (the copper disk being corroded and not signalling the lights are popped-up/down), but I don’t know if that would cause my symptoms. I don’t want to remove and dissemble the motor without knowing that is the cause.



I could buy a brand new relay, but they are expensive, and I don’t want to do that if the fault lies elsewhere.



Are there any tests I can do to isolate the cause of the issue?

 

Ian,

There is a wiper contact on the end of the motor and that has to make contact once the mechanism is fully elevated- it is not too difficult to trace that, and that contact feeds into the relay switch on the lights.

When my relay falled it would lift the mechanism up but it would not switch on the lights. Maybe this is a common mode of failure given the lights run continuously when switch on but the lift mechanism does not. Thus the illumination relay component is presumably locked on passing current more than the rest of the relay. Either way should be easy to jumper the relay contact to test for illumination.

Those things are so damned expensive there must be scope for refurbishment by someone. Last I checked they were close to $200 a pop and that ws some time ago.

I trust you have the wiring diagram for the relay?

 

On the S4 I believe the same set of wipers control the start stop on the headlight motor. The earlier motor did a full 360 sweep to raise and lower, however the S4 and later reverses direction to lower, which is why it has 4 relays inside the headlight relay block instead of 3. If the headlights are raising and lowering and stopping in the correct position, then the headlight contact wipers in the motor are most likely operating correctly.

If the relay isn't closing to turn the light on once they are up, but the motor runs and stops at the correct locations, there are only a couple likely possibilities. 1) the "lights on" relay has failed/bad trigger coil. 2) the IC circuit that supplies the ground path of the trigger coil of the "lights on" relay has failed. I have repaired an early relay assembly by replacing the "lights on" relay. I would imagine it would be possible on the later relay assembly as well, but I haven't seen the inside of one to confirm. I scavenged a relay off a memory seat board from a Range Rover Classic I had laying around. at the time I had come up with what I believed to be possible part numbers that may fit, but never confirmed.

 

I have got the pop-up mechanism working OK but the lights are still causing me problems.



I removed the motor, opened up the gearbox. It looked pretty good in there, the contacts were not worn – however there was a line of black where it had rubbed, so I cleaned that off in case that was causing an issue. I then put it all back and the pop up mechanism all works smoothly.



However, I can’t get the lights to behave.

When I first tried it, the lights popped up, but the light bulbs would not come on.

After double checking the connections in the fuse box, I got it so that it would pop up, but I could hear a switch in the headlight relay would be endlessly turning on & off, and there is an associated flicker in the lights which then DID work (both dipped and main beam), and there is a similar “flicker” noise from the motor. So I deduced it thought that the head-lights were not fully popped up and was still trying to raise them. So I then started adjusting the bolts that hold the bar in the bearing:

• If I dropped the bar lower, it pops up fine, but no lights
• If I move the bar higher, it pops up, but then I get "the flicker", but I do have lights.

There does not seem to be a sweet spot where both work.

If there something else I can adjust or is this just a symptom of a faulty headlight relay, and should I fork out the £140 on a replacement.
I did wonder whether i needed to move the raising arm slightly (i.e. remove arm from motor spindle and refit at a different angle).