N70 hilux no Headlights (12v to headlights, No Negative!)

[Grunt Lux]

Go a weird one,
My headlights started flicking on and off for a while, then seemed to come right (I have no spot ties wired up).
Then one day I jump in and have no hi or low beams at all.
I’ve checked both 20a fuses in the engine bay and have 12v at the common pin for the headlights, it appears I’m getting no ground/negative coming through from the headlight switch.

My tail Lights, dash lights and dash light high beam indicator work as they should, just not the headlights.
I figure I’ve got a broken connection somewhere, has anyone come across this before and can save me pulling the dash/wiring to bits?

Cheers.

[martynvella]

If it is an SR check the schematic, my guess there will be a couple of relays, even a SR5 probably has relays too but it is harder to get a schematic for them.
The relays are a mid point in the circuit and can narrow it down to a primary or secondary side fault.

But first check every fuse in all 3 fuse boxes with a testlight and for heat damage.

[Grunt Lux]

Update for anyone with this problem.
After chasing the wiring and pulling half the dash apart there is a plug under the dash above the clutch pedal.
This has all the headlight wiring and also is the transition point for where the -‘ve for the headlights changes from solid black to white with black trace.

Somehow this plug had managed to come loose.
Plugged it back in and bingo the lights are back.
There is no relay as suggested for the headlights, the -‘ve comes up to the light stalk switch then is switched to the high or low beam. At the light gloves you should always have a +‘ve 12V.
As a temporary fix I wired in some jumper cables to get the lights going.

Now to put it all back together.