Do they make the wiring in these cars from scoobies?

Tonight whilst fixing my rear washer jet, my car developed another electrical "charm".

Now when I put it into reverse I get a "bulb out" warning light, and the rear foglight dimly flickers.

The rear reversing lights, number plate lights and 3rd brake light also go really dim and start flickering when put into reverse.

Out of reverse all is well.

Just had a brand new battery. Alternator tested and was fine.

??????

Multiple bulb faults usually a bad earth. Possibly disturbed something while fixing the washer.

Earth fault, most likely somewhere on the reverse circuit.

Al;most certainly a result of your rear wash leak.

Disconnect each light cluster one at a time and retest for dimming. Check all connectors for crystalised washer fluid/corrosion.