Light switch 90 def td5 2004 lhd

Anyone experience of headlight switch problems.
I've got it out of the housing, and it looks like the headlight contact has been hot and sunk into the back board, not a lot but enough not to make contact. But why ?
Fuses are OK.
Side lights, and dashboard panel lights ok., but switch to headlights and no headlights or panel lights.
Cheers teaboy2

On earlier models it was usually caused by fitting uprated higher wattage bulbs with no relays to take the extra amps off the switch. I don't know but expect the td5 to have headlamp relays?
Extra spotlights fitted?

Yes, it's a common fault with the TD5 headlight switch, even if you're not asking it to power anything extra. Some people fit relays so the full current doesn't go through the switch, or there's a Boomslang loom kit you can buy that's (allegedly) got all the components you need to perform the modification. Although some people on here seem to have had a good deal of trouble with them. So I've just resigned myself to replacing the switch once in a while. They last about 10 years, so it's not too much of a chore.

On a Td5 it is likely to be a failing dim dim relay, although it can also be other things like poor connections and overpowered lights. The dim dip relay was certainly the problem on mine. You can either remove the relay and just jump the connectors in the plug with a short length or wire, buy the correct relay to eliminate the function or modify the existing relay (link). I followed the tutorial on the link to modify the existing relay and this solved all of my issues.

**Warning: Only do this once the fault has been resolved**
You can then either replace the switch or if you are extra cheap (as I was at the time being a student) you can build up the sunk contact with solder and it will then work again.