Leer Dome LED not working properly…

So my dome LED light has worked perfectly since cap was installed in 2021 until yesterday. Now when I push the button, the LEDs illuminate but so faintly that the light doesn’t really emit any useful light.

Brake light works fine. The dome wire is wired directly to the battery. All related fuses are good. I checked the wiring at the junction box at the back of the cap and that all seems ok.

Anyone have any ideas/suggestions? Anyone have a similar issue?

 

If you've got 12 volts going into the led light and the ground circuit is good then it sounds the light just went bad. Time for a new one

 

good ground?

 

Haven’t checked the ground yet, probably because it’s hard to find. I’ll have to trace the wire under the truck to find it.

 

When I wired my brake light and dome light I screwed an eyelet into the sheet metal behind the left tail lamp. It's been a while but I'm pretty sure there's some good metal back there. You might check and see if the canopy guys put a ground there

 

Thanks, I’ll check there for sure.

 

check your power lead mine got really bad and would flicker... the crimp on the fuse wire was bad, replaced that and was just fine.

 

I’ll check that too, thanks!

 

You might also check the contacts on the bulb and its receptacle for corrosion. A bit of steel wool or emery cloth could clean those up.

 

I still have to hook mine up...

 

Troubleshooting continues. All associated fuses are good. I traced the wire that connects to battery and could not find any issues there.

I checked volts coming from battery to fuse, 12.3v

I checked volts at that junction box in topper and had only 2.3v coming out from box to LED dome light. Should be 12v. The brake light works fine.

Any ideas/suggestions out there?
Also, I think there is a wire harness under bed that was added into all that trailer harness wiring that serves the 3rd brake light and dome light. It also seemed ok, nothing obvious.

It all worked flawlessly for 3 years, then dome LED suddenly went dim. It’s not getting enough juice from battery somehow.

 

Now for in-line fuse related question;

-checked voltage at battery: 12.5v
-Checked voltage where power lead for dome light connects to battery:12.5v
-Took out fuse and put probes in where fuse goes and got 11.3v
-kept positive probe in fuse socket and grounded negative probe back to battery and got 12.5v

Could the in-line fuse connector be bad?

 

If you haven't checked yet, I'd pull that tail light and check for ground in that location. Believe that's Leer's recommended spot. My installer did that and I found corrosion happening after only 1 winter. That area actually gets road spray, and if you're in a salt state the cheap screw/connector goes fast.

Good luck!

B

 

I did pull the tail light and no ground. That lead wire from the battery goes all the way to the rear and into an aftermarket wire harness that Leer installer put in. That harness connects to trailer light harness, then red/black/white wires come out and go straight up into the fuse junction box mounted at back of truck bed beside the hatch. Couldn’t find a ground anywhere in the back. The battery is grounded of course.

So if a ground is needed, I’m not sure where to tap/connect a ground back there?

 

Got it. The good news is that should be a cleaner install than the crappy t-tap and half rusted sheet metal screw my installers used!

They are pulling pos/ground/brake off the trailer harness. Assuming trailer lights are working fine, try checking ground between fuse box and trailer connector.

I included the fuse box wiring diagram below. It's probably the black wire, but will definitely be whatever color goes to the ground position in the diagram.



And, I am definitely no 12v guru. Just passing along some of the help much more capable forum members passed to me when I cleaned up my installers mess.

Hope that helps!

B

 

Thanks for the tips B.

So far I can’t find a ground between trailer lights and fuse box. All associated fuses are good though.

All taillights/brake lights work fine, even the 3rd brake light on the topper works and the wiring for that is associated with the LED dome light wiring.

All I really know is that adequate power (for LED) is not getting back to fuse junction box in the bed anymore even though adequate power for 3rd brake light IS.

Also, there is no ground between the trailer harnesses and the fuse junction box (where wiring comes into then out to 3rd brake & dome light). How could this setup have worked perfectly for 3 years without that ground?

 

Pics of said fuse junction box & wiring…

 

If I wanted to add a ground from here, would I need to tap into the black wire?