Howdy
If you are only missing TAIL LIGHTS then the problem is most likely in the wiring from the cab back to the light housing. Many times there is a "splice-job" with scotch-locks
by the rear end for trailer hook-ups and that can cause all kinds of problems.
If you are missing all normal driving lights: front markers, tail lights, cab markers ect... then I would look at the switch itself in the cab. These switches were prone to overheating because the factory ran full current through the switch. If you pull the switch out it should be obvious if it damaged.
That's how I would start....
Hope this helps
1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
2001 Chinook RV, V10 gas
1974 John Deere 1530 diesel tractor
1993 John Deere 455 Diesel lawn mower
1967 GTO, 1989 Honda Transalp
2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
1998 6.5 suburban, stock, daughter's
1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's
1984 6.2 ATS turbo 3500, SCDWLB - Son's
3 kids, 1 wife, 1 dog
Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!