Tail light wiring harness

[rs74]

All the rear lights on my 85 shortbed don't work any more and I suspect a mouse. I haven't got under the truck or pulled the bed yet but can a new harness be bought that goes from the firewall all the way back.

I might have issues with the fuel gauge not reading either. That might be a separate issue. My truck has sat since 06 and I only get it out and start it about twice a year. But that is all about to change if everything goes right. Time to get the ol girl back on the road.