Dodgy Headlamps

Post by **Chris_C** » 05 Dec 2006 02:10 pm

Am at Kate's at the mo, with no schematics, so anyone got any ideas...

My front lights have been playing silly sods, sometimes when I switch them on, they are dim (dipped beam coil is lit though) and the mains don't latch on. Other times, the fronts are bright (I don't think this is due to the main beam coil being on as well, but I couldn't be sure) and the mains do latch (i.e. my grill lights and the light in the dash cluster.

Also with this problem, when the lights are dim, there is no difference between the sidelight switch, and the dipped beam position of the switch (e.g. 1 and 2), both light the dipped beam coil of the main lights (even though you can hear a relay click between 1 and 2 position).

Rear lights arn't affected, I know this is a dodgy connection somewhere, and with the symptoms, reckon its an earth fault, but anyone had it before, or have the schematics to be able to offer an idea as to where the fault may be? I'll be back with my books tomorrow, but don't like driving like this, already had the entire set of front lights come on a dazzle a poor sod randomly... I can't tell when they are latched on or off, so when they start to work proper, the mains sometimes flick on....

Post by **SteveP** » 05 Dec 2006 02:27 pm

Schematics on the way...

Post by **Chris_C** » 05 Dec 2006 02:54 pm

Cheers Steve and Nick for the schematics!

Ok, next question... does the main beam relay latch, or the switch. Something tells me I could have loosened the switch when I was wiring up my electric windows... is this what happens when that top support goes?

Post by **petefarrell360** » 05 Dec 2006 04:01 pm

You mean on the steering column mate? Mine on the vario doesn't seem to move enough to hold on main beam, and doesn't even flicker, or hold the main beam on if you hold the stalk back. It just about worked for the MOT, but was fussy, worked for a few more days and gave up, so I only have dipped headlights now, no main beam. I've just not had time to swap the stalk, as I've another sat waiting to go in to see if that is it.

Pete

Post by **Chris_C** » 05 Dec 2006 05:28 pm

Sounds like the same thing Pete, got tied up working all afternoon, but I had to undo the mounting screws for that switch when I was wiring come to think of it. Hopefully its just gone out of place.

Doesn't explain the lights on the same brightness for two switch positions though!

Post by **pettaw** » 05 Dec 2006 09:34 pm

My best guess given that I haven't got decent wiring diagrams to hand, is that its most likely either one of the two relays that operate the headlights under the steering column.

Or else its a dodgy main lighting switch or corroded contact for position 2, the switch seems to be a dual combination one, where on position 1 it puts 12V to position 1, and then on position 2 it puts 12V onto position 1 AND 2.

Post by **Chris_C** » 06 Dec 2006 11:45 am

Yeah, I'm thinking this more and more tbh, should one of the H4 bulb filaments be lit in position 1 though?

Post by **SteveP** » 06 Dec 2006 11:54 am

Chris_C wrote:should one of the H4 bulb filaments be lit in position 1 though?

Nope

Post by **340GLT** » 06 Dec 2006 12:29 pm

The relays latch chris as the 400 switch i have on my column has a latch and non latch setting and they work on both.
Sounds like a ssemi obvious thing to check but remove the multiplug from the bag of the headlamp and check contacts, i had a similar problem when i knocked it with the spare tyre!!!
Adam

Post by **Chris_C** » 06 Dec 2006 01:50 pm

Cheers Adam, thats dead useful to know. I really have a fealing I knocked something whilst putting the windows in, but I will check the front lamp plugs, cheers dude.

Post by **pettaw** » 06 Dec 2006 07:56 pm

Adam are you sure the relays latch. Not wanting to disbelieve you but why then would the switch have a memory knowing what position it was left in even with ignition off etc.

Anyway, Chris yes one of the H4 filaments SHOULD be lit up in position 1, that's the dim-dip relay working, it puts approx 9V across the bulbs.

Post by **SteveP** » 06 Dec 2006 08:28 pm

Yeah, I'm a noob... certainly does light up one of the H4 filaments up in Pos 1...

Post by **classicswede** » 06 Dec 2006 10:33 pm

I've also had a very similare problem. One lamp on dim dip while the other was on normal dip and when droping back off main it would not come off untill you turn the switch to knock the lights out.
That was caused by a poor conection to the headlamp unit.

Post by **Chris_C** » 09 Dec 2006 12:24 am

Fixed it today, followed the green book schematics back (the Haynes schematics are complete lies, more than standard lying Haynes...) and sussed the two internal relays were ok (after hunting down a relay only knowing its feed wire colours...).

So, knowing the internals were ok, didn't want to test the externals, as the lights had started to play up after I had been wiring something in, so traced the internal to external wire (as it was the only thing internal left!!) Once again, the multiplugs near the bulkhead, and those on the bulkhead into the fuse box were causing issues. They are cr*p, and usually the cause for this sort of thing I find!

Post by **classicswede** » 09 Dec 2006 10:19 pm

I've had various problems in that area.

I think they are probably worth pulling apart and using soem electrical spray to reduce any sorrosion problems.