Boot/trunk light not working

[s2driveruk]

Originally thought it was a blown bulb but having replaced it still dead. Removed the light and checked it direct from the battery and light works fine. Multimeter on the + and - and shows me with 12v. Pish in the switch and drops to pretty much zero, 0.01v, let the switch out and 12v returns.

what am i missing i hate electrics

[Tractor Dave]

If you have good voltage at the bulb when switched on then you must have a poor earth.

[s2driveruk]

And idea where the earth is for the light? Or is it more generalised bad earthing lol

[Tractor Dave]

And idea where the earth is for the light? Or is it more generalised bad earthing lol

I'm not sure on the Coupe, I think its the same as mine. Earth wire will be brown, follow it back and you should find a connection to the body. Take that off and clean it up making sure you have a good contact. I cant remember if it shares its earth with the rear lights. I will see if I can find the relevant pics on my phone.

[newsh]

Very simple circuit.
Power to one side of the bulb.
The switch just goes to ground.
So
Either the feed won’t pass enough current to light the bulb or the switch won’t pass enough to ground it.
Or there’s corrosion on the bulb holder.
Try the same test but with the bulb in place.
Measure from a ground point on the chassis to one side of the bulb then the other.
Clean the bulb holder. W3
Wiggle the switch. F5

[s2driveruk]

Thanks..love the ‘very simple circuit’ i am a complete leccy ludite

[s2driveruk]

Bulb holder is very clean, no corrosion on either connector and spades look ok.

[Tractor Dave]

Thanks..love the ‘very simple circuit’ i am a complete leccy ludite

It's just the far right line, top to bottom you are looking at. Top + to bottom - ground. Switch and bulb in the line

[Mikes2]

It's possibly the loom going into the tailgate broken wires in the top left corner

[s2driveruk]

Thanks all, will pull the rubber boot off and see what i discover.

[LSG]

You can always just run a second earth wire in to confirm your suspicions its a bad earth.

[SteveH]

What's T3r/3? Is that a connector in the loom?

[Bowie69]

Is your new bulb LED?

[s2driveruk]

Nope just an old school one

[newsh]

Thanks..love the ‘very simple circuit’ i am a complete leccy ludite

Lol
Yeah it’s just this bit
12V at the top, chassis ground at the bottom