Help- Electrical problems with tail-lights

[Lippyp]

I hate 35 year old wiring!

I jumped into my truck last night to go the first local cruise of the year and my tail-lights weren't working. Brake lights, turn signals (mine have been converted into UK spec orange lights in the back-up lights) but no tail-lights.

I looked under the bed and this is this god awful crusty plastic terminal block where the p/o has spliced in trailer wiring, the contacts have rusted to hell, wires are corroded and breaking up and I assume the power to the tail light circuit is broken.

The worst wires are the ones actually from the lamp units, it looks like the power lines from the cab have been replaced at some time but these are original and the are rock hard and brittle and covered in paint overspray. Can these be replaced or does this mean new lamp units?

I can remake the connections properly and waterproof them with some self-amalgamating tape but I need decent wires to do this with. All suggestions welcome.