Tail lights not working properly

[60's Kid]

Front lights work great. High beam, low beam, turn signals, and parking lights all work. Tail lights come on bright (more like Break lights--not sure) when turn lights on. No brake lights and no turn signals. Anyone have any ideas?

Rick

[Svtfreak]

Using kit harness and brake lights?

If so, try disconnecting the brake light lead at the tail lights and see if it works. Mine did something similar and I fixed it by disconnecting one but don’t recall which one. Try that, if it don’t work, I’ll go look at mine and see.

[FF33rod]

Long shot.... i was working with the dash harness yesterday and was thinking I would cut out all the wires related to the turn signals since the 33 has that switch on the steering column. However, it appears that one still needs to keep the front and rear turn signals joined at this location. Are they joined in your harness still?
Steve

[JimLev]

With the Ron F harness and the FF LED lights I connected them like this, everything works.
Left Rear
Harness colors. Stop/turn colors
Black---------------White--ground
Tan-----------------Black---parking light
Yellow--------------Red----directional and stop light
Violet---------------Not used

Right rear
Black--------------White---ground
White--------------Red----directional and stop light
Tan----------------Black---parking light
Violet--------------Not used

[RJD]

Not sure if the 33 uses the same lights as the MKIV, but it seems that lately the MKIV tail lights coming from the factory have crossed wires. To confirm they are correctly wired, remove the lens cover of the tail lights and confirm the bright filaments are illuminating when the brake pedal is pressed and the turn signals are operated, and the low filaments are illuminated when the lights are on - not the other way around.

My wires in the tail lights were crossed from the factory. This resulted in the bright filaments being illuminated when the lights were on. Consequently, you couldn't see the turn signals working though they were - the bright filaments washed them out.

See the thread: Wonky Brake Light

[Svtfreak]

Jim and Steve are correct. I had forgotten that point. The purple wire doesn’t get hooked up at the tail lights. And the turn signal wires that says go to the then switch must be tied together. This is because of the turn signal stalk on the 33 that the mk4 doesn’t use. It uses a regular old switch. I remember having to do that now also. I’m fairly certain i recall my lights doing just like yours when the violet was connected.

[Ducky2009]

Two things to try.
Remove the lens from the light. Check if the wires are crossed by turning on the lights on .... then the turn signals. Does the second filament (dimmer of the two) light up when you turn the turn signals on? If so, wires are crossed.

Second, check the factory wiring there the rear harness plugs into the main harness. Trace each wire (by color). Is the gray wire in the main harness gray in the rear harness, etc...
My front harness wires had two wires swapped and I had the same issue.

[60's Kid]

I don't understand your statement "signal wires that says go to the then switch must be tied together"
Everything worked once the violet was disconnected except brake lights

[JimLev]

RJD and Ducky, IIRC the LED tail lights covers don't come off.
Your MK4 lights must use conventional bulbs.

The brake lights should work even with the key off. Check the brake switch wiring.
Have you tried the 4 way flashers yet?

Update, yes these are sealed units.
https://upcarparts.com/40-led-tail-l...42-48-ford-car

[60's Kid]

ok will check the brake switch. yes 4 ways work . Now everything except brake lights work

Thanks Rick

[JimLev]

The 12 volt feed from the fuse block is an orange wire, says BRK FEED. This wire should have 12v on it all the time. If it does then put your meter lead on the other terminal and push the pedal, you should get 12 volts there too.
The other terminal on my switch has a violet wire and a gray wire connected to it. I know the violet isn't connected at the tail light end, but don't recall where the gray wire goes to, maybe it's the one I used for the tranny?
I've added more info to post 4 above.
More info tomorrow, I need to find my notes.

[Svtfreak]

I don't understand your statement "signal wires that says go to the then switch must be tied together"
Everything worked once the violet was disconnected except brake lights

The nonsense that I posted don’t matter if you have it working. You got the signal wiring right. It was supposed to say the wires that go to the switch for the mk4 had to be tied together on mine. Not sure how I botched that up lol.

Time to start tracing back for your brake lights. Check the switch.

[60's Kid]

got it ...the brake switch was set too tight. backed it off and brake lights work now. not easy with body on.

thanks guys

[Dduty]

Thank you for passing on your knowledge!
You just solved my last glitch.

With the Ron F harness and the FF LED lights I connected them like this, everything works.
Left Rear
Harness colors. Stop/turn colors
Black---------------White--ground
Tan-----------------Black---parking light
Yellow--------------Red----directional and stop light
Violet---------------Not used

Right rear
Black--------------White---ground
White--------------Red----directional and stop light
Tan----------------Black---parking light
Violet--------------Not used