Headlight problem

Hi all. I've a problem with my full beam on one headlamp.

Side lights - both fine
Normal dipped - both fine
Pull stalk to flash - left headlight flashes, right headlight stays dipped
Push stalk for full beam - left headlight full beam, right headlight goes out.

Can anyone help?

Cheers

Tez

rh main beam filament?

The Mad Hat Man said:

rh main beam filament?

Click to expand...

That's what I thought, especially as I was still on sealed units, so. I've been to bolt on bits today and bought some shiny new crystal halogen jobbies.
Still got exactly the same problem

why dont yu just check the headlights?
then the earths
then the wiring back to the stalk.

Bad connection under wing

The Mad Hat Man said:

why dont yu just check the headlights?
then the earths
then the wiring back to the stalk.

Click to expand...

I'm guessing the headlights are fine, as after replacement with new units I've got the same problem.

As for testing earths and switches I don't really know how to do it

I was hoping for an answer along the lines of "cut the green wire and hit the ref one with the big hammer" as that's the kind of level I can operate on when it comes to electrical fault finding.

Take an old light unit like an indicator etc, attach a piece of wire to each terminal and you have a homemade circuit tester.

Test it on the battery every so often so you know it still works

Sounds like a bad connection between the switch and the light - obviously.
On mine this is a blue/white wire. Locate it under the wing - part of the three way plug that goes to the bulb.
You should be able to trace this back to the main wiring loom plug - in the engine bay on mine. The most common place for them to fail is near the wing end, where they are exposed to crap/weather. As above, an old sidelamp unit makes a useful tester. Becuase a connector looks OK, doesn't mean it is. Separate it, wiggle, check again.
Older wiring can just rot away beneath the insulation, again usually where exposed to the elements, which is everywhere on a defender.

I've got mi sen a multi meter and been having a play. Headlights fine. Earth seems fine as does the dipped beam wiring. The problem is when I turn full beam on. Earth still seems ok but one wire has around 8.5 volts and the other 0.85 volts so I'm guessing there is a short somewhere. Now I just need to try and get to all the wiring.