[indetrucks]

Pretty sure I have some wires backwards on the tail lights....

When braking with left turn signal on, right side tail lights go out.
When braking with right turn signal on, left side tail lights go out.

When braking and emergency flashers are on, tail lights do not flash... left/right directional indicator on dash stays lit (no flashing).

So basically, as long as I'm NOT braking, everything works as it should.

Does anyone know what wires I might have crisscrossed? Here are some photos of my tail light socket set up. Sadly the sockets came with only back wires and not color coded. But they are the best I could find that didn't keep popping out.

Driver side


Passenger Side

[kate`s67gto]

First if you have the hazard flashers on and step on brake pedal the lights will stop flashing. Brake lights over ride hazard flashers.

The bulb are your answer to what wire goes to turn and brake wire.
The heavy filament is for brake turn signal.
So the lighter filament is running light.
So left and right running light wire color is brown.
So right turn brake wire color in harness is dark green
Left brake turn wire is yellow.

Hope this helps.

[indetrucks]

Originally Posted by kate`s67gto

First if you have the hazard flashers on and step on brake pedal the lights will stop flashing. Brake lights over ride hazard flashers.

The bulb are your answer to what wire goes to turn and brake wire.
The heavy filament is for brake turn signal.
So the lighter filament is running light.
So left and right running light wire color is brown.
So right turn brake wire color in harness is dark green
Left brake turn wire is yellow.

Hope this helps.

Thanks for the hazard flasher clarification. Glad that's eliminated.

As far as the bulbs go, all four bulbs in the back are dual filament. It was my understanding that when you used your turn signal, the complete left or right side lit up (two bulbs each side).
When you hit your brakes, all four bulbs lit up (brighter filament).
When you have your driving lights on, all four bulbs also light up (lighter filament).

Am I wrong? (67 GTO)

[rexs73gto]

That is correct but it sounds like you have 2 of the bulb sockets wired backwards. Thats why the bulbs go out when you step on the brake pedel. Retrace your wires to make sure both of the bulbs for the turn lamps are on the correct side of the socket & do the same with the oppisite side. Sounds like you got in a hurry & cut all the sockets off at once & now there wired backwards on each side on 2 of the sockets , 1 on each side. Take them back apart & wire them correctly . If you need help in knowing where each wire gos & where each wire is connected to each socket as far as which line that goes in the either the black wire or the yellow/green wire.

[kate`s67gto]

Another way to determine what contact in socket is for what.
Is by turning on the hazard flashers and using a circuit tester touch each contact in socket to determine which is for brake turn. Then make sure the bulb heavy filament contact is making contact with contact in socket. If not switch the wires around.

[pngoat]

It could also be a case of bad socket grounds. I see you have metal sockets. Run a wire from each socket housing to a bare spot on the body-not the tail light housing-and see if it improves. Also check your engine ground straps for solid clean connections. Hope this helps. Good luck.