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Strange headlight behaviour

PostPosted: Sat Jul 15, 2017 4:27 pm
by Tresidder17
I recently bought an MY07 3.0r spec.B liberty. Its been well maintained and is in great condition. When I went for an inspection, it had both parker lights and the left high beam light not working. The owner said they were just blown globes and offered to replace them but i didnt have time to leave the car with him for a few days until he fixed them... stupid me.

I've got the car home now and went to replace the globes. Both the parker lights were blown as the owner said and i replaced them with no problems. However, the left high beam is not the same story.

The high beam globe appeared to be in perfect condition so i swapped the globe with the globe on the right hand side. the globe from the left side now worked in the right hand headlight however the globe in the left hand headlight (which had been working fine in the right hand headlight) was not turning on so I think its safe to say the globes aren't the problem.

I went on to check all the fuses in the car (at least, i think i found *all* of them) and found no issues here.

Im starting to run out of ideas on what could be the possible cause of this problem. Any suggestions or a wiring diagram would be greatly appreciated.

thanks guys

Re: Strange headlight behaviour

PostPosted: Mon Jul 17, 2017 11:42 am
by fedaykin
Relays, plugs.
See if the plug is getting voltage when you high beam.

Re: Strange headlight behaviour

PostPosted: Mon Jul 17, 2017 5:40 pm
by teK--
Have you checked the plug for voltage with a multimeter,? Then try back probing the plug to ensure a true result. mine was giving a false negative result, due to the plug being slightly melted inside where it was not obvious. After I changed the plug the bulb starts working again and was much brighter.

Re: Strange headlight behaviour

PostPosted: Fri Aug 11, 2017 7:49 pm
by Tresidder17
Okay so i've finally got around to having another look and this is what i've learnt

I first checked the headlight relays, didnt have a proper way to test them so i switched the RH relay with the LH relay and tested the headlights. Nothing changed so im guessing they are fine

The more interesting things now start.

I realised that when i go from low beam to high beam. the right HID (the completely working side) seems to go from a low beam mode to a high beam mode where the light shines a little higher (and possibly brighter but im not sure) however, the left hand side HID does not do this.

I then got out the multimeter and tested the voltage in the plugs for the high beam lights.
With the high beams off: the RH light i got 12v in one wire and 14v in the other wire. on the LH light i got 0v in either wire.
With the high beams on: the RH light kept 12v in one wire and nothing in the other wire. on the LH light i got 12v in one wire and 14v in the other wire
Honestly not sure what to make of this information

Re: Strange headlight behaviour

PostPosted: Thu Aug 17, 2017 11:36 am
by fedaykin
Sell it and buy a WRX :P

But, you can either take it to an auto electrician, or start tracing the factory wiring, or wire in fresh relays/plugs for the headlights.

Re: Strange headlight behaviour

PostPosted: Fri Aug 18, 2017 10:17 am
by bigBADbenny
Start with the diagnostic procedures & schematics in your fsm:
Download your adm postfl fsm here:
https://www.google.com.au/search?q=site ... ent=safari