Tail lights

[Red chevy 82]

I have a 1982 c10 305 custom deluxe. I've had it since 1993, it just went through engine overhaul, rebuilt transmission and body shop. All the lights worked fine before. Now only the front part of truck lights work and nothing in the rear works. I've replaced all the light bulbs. Has anyone had this problem can anyone help me please? Tanks in advance.

 

[RetroC10Sport]

Ground on the frame.

 

[74 Shortbed]

Check all grounds..

 

[towman]

if the body shop pulled the bed back to paint the back of the cab check to see if they plugged the rear harness back together and as everyone else says the grounds