God, where do I start? Right. Fitted new halogen lamps. Everything worked fine. Rear fog lamp switch was a bit iffy. So I decided to fit a new one. Thats where the problems started. Switched em on. Checked the back and "thats nice and bright" I thought. Turned back to the cab and smoke poring from the instrument panel. Ripped the new switch off and then no headlamps or side lights. Dip switch leads were part melted. Fitted a new dip switch. Checked all the connections against the manual. No dipped beam. Main beam is fine. Out with the instrument panel. Checked, checked and re-checked against the book. Rooting around I found the earth lead running from the inspection lamp socket burnt out. No other sign of burning anywhere (I`ve had a good root around the loom - original - and no signs of burning there either). I have circuit tested the new dip -switch and all contacts appear O.K. This is what I`ve got:

Headlamp switch on - Side and tail O.K.

Dip switch:

Main beam O.K. - main beam element lit
Dipped beam - nothing
Flash - O.K. - The dipped beam element lights

Therefore both the head and dipped beam circuits seem O.K. i.e. power is getting through (blue/red and blue/white).

Totally fumoxed. Day and a half I `ve been at it.

109 is 12 volt with I believe the fog lamp circuit. I have disconnected the triple bullet connetor to the fog lamps; therefore no circuit. Incidentally the fog lamps only came on with dipped beam, thats before I changed the switch.
Mike R

reckon it's gorra be burnt contacts on the headlight switch (dip position).

aye, must be the switch contacts. although i found me headlights stopped workin when i washed all the mud off the insides of the wheel arches and headlight cables, so logically i think that i'll need to buy some replacement light mud

I had this problem with mine, like the others say its the switch contacts. Get a new switch in, and make up a new earth wire and you should be sorted. I accidently shorted all mine out again while replacing the switch so be careful..
They are real easy to change just two bolts/screws to the column and swap over all the wires from the switches and other leads. Hope this helps.....