Only 8v at the fog light

Hi everyone, been a while since I’ve been on here, anyway I have been trying to fix my fog light on my 300tdi defender 1994, it isn’t lighting up when switched on.
I am only getting 8 volts at the bulb holder which I guess is not enough to power the bulb?? ( this is with engine running and good battery). My dash light works to show my fog should be on. I’ve checked the rocker switch everything seems ok there, I have a light blue wire on its own and then red and a red and orange wire together coming from the back of the rocker switch. At the bulb there is a red and orange wire and a black (earth) wire.
Just don’t understand why I am only getting 8v, advice very much appreciated

What voltage you got at the switch?

Do not assume the earth for the fog lamp is any good

Ok, will check at the switch and also try fresh earth if I’m getting 12v at the switch .

Naylz said:

Ok, will check at the switch and also try fresh earth if I’m getting 12v at the switch .

Click to expand...

If it all looks good check the loom where it goes into the chassis drivers side inner chassis face below the bulkhead and where it the comes out of the chassis drives side rear, you might have to pull out a few inches to get a decent look.

Ok, update time. Problem now solved, I did have a very dodgy connection where the loom had been spliced to the tow bracket wiring, all sorted now. Even spotted my reverse lamp also not working so I have fixed that too Have to say the bulb holders are not great on defenders

Naylz said:

Ok, update time. Problem now solved, I did have a very dodgy connection where the loom had been spliced to the tow bracket wiring, all sorted now. Even spotted my reverse lamp also not working so I have fixed that too Have to say the bulb holders are not great on defenders

Click to expand...

If you have one that uses the old bullet connectors the bulb holders are basically disposable. They are only a couple of ££ and it shows, the manufacture quality is appalling, but at that price you can just replace them regularly when you run into a problem.