Brakes cause left turn signal to fail

My 1996 Tacoma with 296,000 miles has an electrical quirk. My left turn signal works but as soon as I apply my brakes it stops blinking. My left brake light is also very dim/does not work. I have no clue what this issue could be, anyone have any suggestions?

 

Have you inspected that bulb or the bulb socket yet?

 

LED or regular brake light bulbs?

 

Check your left tail light sockets .

Clean all the sockets you May have some sort of grounding problem

If you have one of those trailer light converter boxes they like to cause all manor of light problems as well

Physical damage to the rear light harness .

These are the only places these different circuits are close together

 

Have they always been this way? Check your housings for your taillights too they may be corroded.

 

Is it both the front and rear turn signals? Do you hear it stop blinking on the instrument cluster too? Inspect for continuity and voltage the frame wiring underneath the driver's seat (specifically the G-W and G-B wires) I suspect the G-W wire on that section of harness may be shorting out on the chassis somewhere. I'd also take a look at the cowl wiring and junction block #3 behind the left side of the instrument panel. If the front turn signal goes out, also inspect junction block #1 behind the lower finish panel.

 

Had the same issue you’re describing. Turn signal would work until I hit the brakes, then just a steady glow on the instrument cluster. It was a broken/corroded wire in the taillight harness. I took the lens off and inspected the wires. It’s been a while but I recall the fix required crimping and stripping. I could take it off again and take a couple pics if needed.