Originally Posted by humdigadi
Thank you for the reply and I apologise for not adding that. It is indeed a 1997 PFL car. It is a RHD 4.2 Quattro Sport.
Sorry to sound stupid (I'm not a smart guy when it comes to cars!), when you say you think it's the switch, do you mean the switch in the stalk?
The reason I didn't think it was that was because of the change in voltage at the bulb plug when I pull the lever (videos in the UK forum post).
Sorry, I only looked at the first video which seemed to show no response from the pulled back (flash) position.
1st, as I understand (from videos), you have the meter connected at the headlight connection (behind the bulbs)?
If so, it looks as though the problem could be with a connection there...maybe passengers side only(?). I'd look closely at the contacts in the connector and on the bulbs themselves...maybe even try a new set of bulbs.
I may have read this wrong, but wiring diagrams show that the high beam circuit doesn't even pass through the lighting module or any relay, just a simple on/off circuit at the switch and separate dedicated fuses for left or right high beams.
Again, judging from your tests, a problem at the headlights (connections/grounds) themselves...not the switch or light relay.
Just a long distance guess from the info available.