Location of grounds for lights

[Undercover87T]

Having an issue with my rear lights. Body shop installed LED tail lights, 3rd brake light, and one LED flasher. Left brake lights work intermittent, when they do work the 3rd brake light doesn't work. Also the 3rd brake light socket melted to the housing. All other functions work. Also installed relay harness for HID lights to take save the load on the headlight switch. Before these changes were made, everything worked fine but with the headlights on, my left brake lights were out. Front grounds on the fenders are good and clean. I suspect a ground problem in the rear but need to know where the rear ground(s) are for the tail lights. I also have a new AC Delco brake light switch that I may swap in.

 

[bpman1234]

did you fix this ?

 

[Undercover87T]

Nope. As of right now everything is working except the left turn signal. All grounds I can find test fine, all 3 lighting fuses have power, flasher and relay work, but I have no power on the yellow wire in the trunk for left turn. Somewhere between the column and the trunk is where the issue is.