Headlamp woes (for a change)

[Brianc]

That concides with my thoughts

I suspect the limit switch in the headlamp.

Its not a big deal really . Just when lights are switched off the headlamp pod goes down in time with the other, then pops ipnand down once before settling down in the down position.

[Monkeyzak]

When only one of mine was working it was the thermal coupling. Replaced and they both worked

[Brianc]

What is the thermal coupling?

And where is it located?

Thanks

[dursleyman]

What is the thermal coupling?

And where is it located?

Thanks

I think they mean the headlight main circuit breaker which is a small unit about 1/2"-3/4" square that lives by the fuse box. This is a picture of mine, its the small item with the two brown wires at the bottom.

[Brianc]

Just thinking i might switch the left and right run relays over to see if that causes my problem to mve from left to right!!!

Other than that im guessing the problem is in the motor unit itself

[littlepippin]

When your headlamp gets to the down position, there is a position switch in the motor control unit that closes one circuit and opens another, and at the same time you would hear BOTH relays switch over. This may not be happening correctly in your case.
Blue/purple wire and blue/brown wire, and I think the bullet connectors not the red 3 pin.
Could you get your meter probe in and check them (if and when you get voltage and how much) while still connected ? Might save you taking the pod off the car completly.

Try and see it as the headlamp motor circuit (forward of the relays) is ON ALL THE TIME you are not turning a motor on and off with the dash switch - you are just switching from one circuit (up) to another circuit (down) via those relays.

[andyf]

Just thinking i might switch the left and right run relays over to see if that causes my problem to mve from left to right!!!

Other than that im guessing the problem is in the motor unit itself

Makes sense and worth doing. And I know we have covered this, but I would still clean the headlamp switch contacts, it was only one of my pods playing playing up and a clean cured it. I cannot figure the logic of why only one would be affected but it was.

[Brianc]

Thanks fellas

[Brianc]

I have been doing some research on the net and also dismantled a spare headlamp assembly i have and now i think i have a good idea how this convoluted electrical system works !!!!!

So to summarise: my left hand headlamp continues to pop back up once then settles down after either a flash or using main headlamp switch.

I have cleaned all the contacts as advised and the problem persists!!!

Next is to swap over the left and right lamp relays over but i have a question . Do i have to rememove the fuse board to get at these????

If that doesnt cure it im guessing my problem could be in the limit switch on the left hand motor?

It has been said that the main switch may be faulty but i cant see how that would result in these symptoms ?

Anyway work stops now as im off to the cumbria steam show with the 7 v8

Thanks

[littlepippin]

You dont have to remove the fuseboard. The relays are just attached to it by a screw, not an actual part of the assembly like a modern fusebox.

Not a difficult job technically, just a bit of a stretch to get down to it. There should be an inspection hatch at the back of the glovebox, and enough slack on the cables to pull the relays down toward the footwell to work on.
I remember also carefully opening up the relays to clean up the contacts (they were the older drum shaped type) but just do your swap first to eliminate them from your enquires....

[Howard_B]

You may find the drawings I posted a few months ago which include a detailed explanation of the operation of these odd units help you trace the problem. They can be downloaded from the attached links:-

https://drive.google.com/open?id=0B0OCjgNgn85aem1SSVQ3cjJJZkk
https://drive.google.com/open?id=0B0OCjgNgn85aaHl0b3lDTi1kbVE

The details are on sheet 2

Howard