Headlight issues...

woody · Post by **woody** » Sat Apr 29, 2006 6:27 pm

One one hand i'm glad they're not right as they're so poor on the other hand i've a bit of work to do...

Firstly, my driving lamps come on dimly when the dipped beam is on. Is this supposed to be the case?

Secondly, my pass side D/L and Driver side H/L as both very dim when on - i suspect a bad earth, but being not too hot with electrical things, i can't work out where they earth.

Thirdly, my D/L brackets have some serious rot. The Pass side has failed completely (thankfully the wires have held it in before i realised) and the drivers side is 50% gone. I've got new 111s/160 brackets from lotus and had them blasted and painted 'spinner cone' black as the standard of paint (and indeed everything else about them) was sh*t.

I've also got a setof 90/100w H4's to go inti the headlamps when all is sorted out, so i should be able to see at night by them.

Any help with the first two greatly appreciated.

Post by **simon** » Sat Apr 29, 2006 6:31 pm

Your driving lights should only come on when you switch to full beam.

woody · Post by **woody** » Sat Apr 29, 2006 6:34 pm

feck

thought so.

Full beam on

Dipped beam on (the pass side D/L is also on very slightly)

MacK · Post by **MacK** » Sat Apr 29, 2006 9:03 pm

Bad earth could be the problem, and the corroded brackets 'may' be the part of the problem. (not sure though, as I don't what the wiring is...)

Are all the bulbs okay? (front and rear)

Sorry can't help further.

robin · Post by **robin** » Sun Apr 30, 2006 9:22 am

MacK wrote:Bad earth could be the problem, and the corroded brackets 'may' be the part of the problem. (not sure though, as I don't what the wiring is...)

Are all the bulbs okay? (front and rear)

Sorry can't help further.

The corroded brackets are nothing to do with it - they are purely structural and not earthed.

The problem is a bad earth for sure.

The current is flowing down the cable to the dipped beam light, through the bulb to it's (disconnected) earth connection which is shared with the main beam.

From there it travels back through the main beam part of the bulb to the main beam relay (which is obviously off) and then back to the drivers light (which is on the same pin of the relay) and then through the drivers light bulb to the drivers light earth (which is properly connected on your car).

So you have three bulbs in series, essentially, which is why they all glow so much dimmer than they should.

As the left and right hand side lamps appear to share the same earth wiring (according to the wiring diagram) I think you are looking for a corroded earth terminal between the front harness connector and the the drivers side headlight - if you disconnect the plug on the back of the headlight I think you might find one or more corroded pins in it. If not, you will need locate and disconnect the FHC (Front Harness Connector), which is at the drivers side of the front compartment, and check for corroded terminals. All the earth wires are black, but any corrosion should obviously be cleaned (WD40 and a gentle working over with a small flat blade screwdriver work well).

When remaking any of the connections I would be inclined to put some silicone grease in them (waterproof) which will stop moisture ingress and hence corrosion.

Good luck!

Robin

woody · Post by **woody** » Thu May 04, 2006 3:29 pm

Looks like mosture ingress has caused the bulb connector blocks to short and melt a bit, causing the problems. The driver's side is ok now - but i haven't touched the pass side.

I'll get H4 connector blocks off of another car at the scrappys tommorow, chop off the old ones and solder on the new ones. Then seal the block to the wires with a big bit of heat-shrink and a tie-wrap.