Tail light woes

[Alfadad]

91 Comanche 6 cyl/ 5 spd/long bed 4x4. Having issues w tail lights. As you know, from top to bottom, 3 segments. On both sides: Top : brake light and turn signal. Middle: also brake light and turn signal, Bottom: back up light. All are working,but w headlights on, I have no constant tail light. ( Brake and blinkers continue to work w headlights on). I can't figure this out. changed all the bulbs, refreshed ground wire behind driver's tail light. Could this be the headlight switch? Which segment should light up w tail light function? Thanks in advance. Ken

 

[JMO413]

Mine was a wire someone had spliced in at the left front running light. When I bought the truck it had an extra set of trailer lights under the taillights that they used as taillights. They were just wired to a switch. It took me about forever to find that splice. I would suggest tracing all wires in that system back to front. Gotta love Comanche wiring gremlins!

[Torq_Shep]

 My old 89 had this problem and it was a wire that got chafed at the clutch linkage. I ran it with a seperate switch for 6 months before I figured it out.

[Pete M]

there's a connector at the rear near the tire that is known to have corrosion issues inside. top 2 segments should both light up with headlights.  you did put in the double filament bulbs, yes? 

[Alfadad]

Yes , double filaments. Ouch , the rest sounds painful. will need to be diligent Thanks all.