I bought some new repop tailights (Thailand) for my 1977 pickup but the wiring harness plug (rectangle 5 conductor) is different than the OEM version (square/rectangular - 4 conductor plus a separate wire with spade plug for the tail light). Has anyone made this conversion and can tell me what wires go where?

 

Do you have any pictures of the new wiring pigtail and the original ones on your truck?

 

Your factory harness will have a total of 5 wires going to the rear tail lights. Your harness should have the same color code as my 1978/79. My harness color code:

Grn- parking
Grn/yel- R turn
Grn/blk- L turn
Red/purple- backup
Grn/wht- brake

Hope this helps.