Reversing light dash warning light problem earth?

Hey, this is most likely an earth problem, but where?

When in reverse, reverse lights work as they should. as do all other lights.

The dash warning light (for reverse) is dim, and also is dim when brake lights come on.

Everything else on the car and dash is working AOK.

So far, i've only removed rear lights and cleaned and checked, all appears OK there.

So where is the earth connection associated with the Reverse (rear) lights??

What is the dash warning light for reverse?

Sure it’s not the dash light for the fogs? That’s common when there’s a bad connection somewhere.

Not heard of a reverse light on the dash, which do you mean?

As for the other earth points, if you remove the plastic trim panel that runs along the bottom edge of the boot you'll see an earth wire either side.

They can corrode especially when the black rubber grommet boot stops leak water and it runs down to the earth points.

It's more likely the black earth on the cluster wiring itself

Sorry, I should have put my thinking head on, indicator is indeed the rear fog dash warning, this works as normal, however it comes on very dim with reverse and brake switch (I've never used the fog lights so not noticed before these before),
I will check out the earths like mentioned behind the boot trim panel like suggested tomorrow.
Sorry for the confuse.com