LED Tail lights replacing incandescent.

[grendel]

Hi Brothers and Sisters,
I have an M932A2 that originally had plastic brake light housings and incandescent bulbs.

They got smashed up, so I replaced them with aluminum housings and LED tail lights.

Now the LED brake lights are on, when you turn on all the lights. As in they're stuck on bright and no change when you press the brake pedal or turn signal.

Another member mentioned you had to swap wires.

Any ideas?

 

[gimpyrobb]

Well its either the switch for the brake lights or the wires are hooked up wrong. Have you taken 24v to each of the leads to verify what they do? I got some that didn't have any tags and that helped a bunch.

 

[Gunzy]

Check to make sure the trailer brake handle on the right side of steering column(opposite the T/S switch) is pushed ALL the way forward. ANY movement to the rear will apply the brake lights. Ask me how I know, cost me a brake light switch when I didn't need one.

 

[grendel]

I am sure the trolley handle is forward. I checked the wiring numbers, they are correct. Thought about a ground issue, will check that.

Is there an LED brake light switch? Thought there might be a difference in resistance.

 

[swbradley1]

I put the LED tail lights on my 5-ton and they just worked. I hooked them up to a battery charger first and tested each lead first though to make sure the labels were correct.

If it were a modern vehicle with a power control system for lighting in it I would say it was a resistance problem but the old trucks are pretty brain dead simple.

Do what Gimpy said and run them all one at a time with 24v and test each lead on the truck with a meter and match them up.

 

[Tinstar]

When I replaced all mine with LEDs, one tail light set was labeled wrong and did the same thing.
A multimeter solved that and I relabeled the wires.

Took about an hour for a 10 minute job but all is good now.

Don't forget to update your signal flasher to the new style for the LEDs.

 

[Recovry4x4]

Where did you find LEDs in an aluminum housing?

 

[grendel]

I bought the LED's and housings separately.

Sounds like I have a mislabeled wire.

 

[Recovry4x4]

Ah, got it.