Dimbulbs...

[wrecked]

I installed LEDs everywhere about a year ago, even on the truck and I noticed the right rear lamp (single, dual action like an 1157) glowed dimly with everything off. Fast forward to recently and the installation of a hitch and 7 pin electric connector etc etc etc and, now both tail lamps glow dimly! I've traced it to the brake circuit and my multimeter reveals ~5v and a whopping 27 milliamps. These are decent quality lamps and I'm thinking they are merely showing what's always been there: a very insignificant, parasitic draw on the brake circuit.

Am I kidding myself about that? Or should I doggedly chase this down and eliminate the draw, at the cost of my marriage and sanity - likely both - which upon reflection might not be such a bad thing...

Forgot : 88 f250 7.3idi with a custom box yada yada yada...

 

[chillman88]

My 91 does the exact same thing. I haven't bothered to figure it out yet.

 

[BlindAmbition]

I've had weird bulb issues like that fixed by flipping the bulb, though you cannot do that on an 1157. Tail light circuit is part of the the running light circuit I believe, I'd be checking run lights as well. I had run lights sticking on and I had to go through them one at a time, flip, then check to see if issues were resolved, then move to the next one. Don't forget interior and cab lights as part of that if you have them.

You might be able to fix it by adding a diode as well, like linked below.

https://www.amazon.com/6A-50V-Rectifier-Diodes-4-Pack/dp/B007Z7OQ5G/ref=sr_1_13?crid=3JW4KAYUQ567J

Add it to the positive side. The | mark represents the grey band below.

Power from circuit ->| power to bulb

 

[Noiseydiesel]

Are you using a name brand LED? Sylvania?
Or cheap land of almost?
I had the same problem with a dash mounted LED.
I changed it to an incandescent. No more glow.
Sylvania didn't make one for my application.

 

[snicklas]

We have seen this on E4OD trucks…. The TECA passes a small amount of current through the brake light circuit. It can be enough to light LED bulbs…. Just a thought….

 

[Nero]

Doesn't LED tail lights also cause the transmission to shift funky too?

 

[snicklas]

Doesn't LED tail lights also cause the transmission to shift funky too?

Yes it does... Just like on some of the earlier trucks, the hazards will make the converter lock and unlock....

 

[wrecked]

Apologies, I wasn't getting notifications on this. These are nos Grote sealed truck lamps with Sylvania front turn bulbs and Chinese headlights. All leds. I plowed through all the wiring looking for damaged or cracked insulation, no issues found. But the brake switch itself wasn't working properly so I got one from the wrecker, et voila! They ain't glowing no more.

Before installing a brake controller I was not aware the brake lights would flicker with light braking. Neighbor said he was gonna tell me about it a while back but, I routinely out-fish him and he lost the motivation to help me in any way, shape or form.