1973 FJ40 Tail Light Wiring Help (1 Viewer)

[Sando Serious]

Searched and read through several threads but still running into some trouble.

Replacing some Jeep style tail lights previous owner had on with OEM tail lights. The Jeep style lights have three wires. OEM just have the two bullet connector wires. I was under the impression the solid green OEM wire (turn signal?) should connect to the red pigtail and the green/white (brake light/running light?) OEM wire should connect to black.

When I connect it this way I get brakes but if I turn the signal on I lose them. I also get tail lights but lose that as well if the signal is on. If lights are off and I’m not stepping on the brakes, then turn signal works. I’ve only messed with the driver side as this point. Passenger side looks even messier.

Below is the original connection. Black went to black, red to red, and white to green.

Here’s the style of tail light I removed.

Here’s the passenger side connections. The third wire from the Jeep style lights was connected to the female connector hanging too near the top.

 

[B y r o n]

Maybe the '73 wiring diagram will help.

 

[FJ40Savvy]

Looks like you have a PO issue. The factory lights are grounded using the mounting bolts from the lights and in the OEM harness there are only two wires going to the lights. Even though the wiring harness in my '73 truck is OEM, it doesn't match wiring diagrams shown in the link. It seems to be a combination of schematics.

I think that the OEM lights that you have match the "70 wiring diagram. The solid green wire should be your park lights. The green/white would be your brake/signal lights. I would suggest buying multi-meter to help with the troubleshooting the previous PO present.

 

[Coolerman]

1973 OEM Color Code for rear chassis wires
Green = Park/Tail/License/Marker lights
Green/Orange = Left Brake/Turn
Green/Yellow = Right Brake/Turn
Red/Blue = Reverse Light

Real OEM tail lights have matching color wires, but aftermarket lights may not. My aftermarket tail lights use Green/White for the Brake/Turn and Green for the park.

So you would connect the Green wire from the rear harness to the Green wire on the tail lights and the harness side Green/Black and Green/Yellow to the Green/White on the lights. Make sure the lights are grounded well through the mounting bolts or they will not work.

 

[Sando Serious]

1973 OEM Color Code for rear chassis wires
Green = Park/Tail/License/Marker lights
Green/Orange = Left Brake/Turn
Green/Yellow = Right Brake/Turn
Red/Blue = Reverse Light

Real OEM tail lights have matching color wires, but aftermarket lights may not. My aftermarket tail lights use Green/White for the Brake/Turn and Green for the park.

So you would connect the Green wire from the rear harness to the Green wire on the tail lights and the harness side Green/Black and Green/Yellow to the Green/White on the lights. Make sure the lights are grounded well through the mounting bolts or they will not work.

Thanks! I was able to figure it out with some previous guidance, but I'm fairly certain there was a grounding issue. All is good now!