No tail lights, good fuses and everything else works

I have been trying to figure out my tail light issue on my 2005 DC, 4wd with a tow package. I noticed a few nights back I didn't have tail lights, this truck is new to me so I'm sure they haven't worked since I've owned it.

I assumed it was the bulbs so I bought new ones and installed them without any resolution. The bulbs are factory bulbs, 4773 bulbs. The brake lights, turn signals, flashers, reverse lights and headlights all work. I have checked all of the fuses in all 4 fuse boxes and they are all good.

The tail light housing are CAPA aftermarket housing and probably harness, they are all factory type bulbs with no LED's.

I also noticed that the bulbs were burned out in the light on the top of the cab, I pulled those bulbs and currently, there aren't any bulbs in the upper light because I have a topper on anyway.

I was thinking maybe a broken wire somewhere but it seems weird that it would only effect the tail lights on both sides and not just one side or any other functions of the bulbs.

I'm curious if anyone else has dealt with a similar issue, it seems like the most likely culprit is the aftermarket tail light assemblies.

 

You say "with A tow package". Is it the OEM tow package, or some other tow package.

Check if the 3rd brake light works.

If it doesn't, it's likely the fuse in the dash, or maybe water intrusion into the fuse block.

If it does, but the tail lights in the rear don't, you likely have a wire-splice issue. Like, a previous owner is a fucking idiot and used garbage wire-mangling taps like these to splice something in, which nobody should ever use, and the wire corroded/shorted. It's often the cause. Look for taped sections of your harness behind the driver tail light, then trace from that wire bundle, along the bumper, over to the other passenger tail light looking for evidence of splicing.

Oh ... and never use bullshit garbage t-taps/scotchloks/quicktaps/etc for anything, they butcher your wiring, its casing, and sets the wiring up for premature failure.

​

 

It has a factory two package that it came with new. I checked every fuse the only ones I wasn’t sure of are the bolt in fuse things under the hood. I’ll have to pull the topper to check the upper lights, I know the bulbs were both burned up and the plastic was melted above them. 7 just left them out since I have the topper and it can’t be seen.

 

The “tail” fuse is a 15a in the instrument panel fuse box. Use a test light to see if you have power on both sides of the fuse when the switch is turned on.

Do your front park lights or rear license plate lights work? Can you hear a relay click in the dash when you turn the switch stalk from “Off” to “Park / tail”? (First click on switch stalk)

 

I had a taillight that would not illuminate despite new fuses, new bulbs and bulb grease. Turned out it was the short harness that plugs in under the bumper. Fortunately local dealer had it in stock.

 

Was it just one side when the harness was bad? Mine is both so I feel like that isn’t the issue. They appear to be newer harness as well.

 

You'll know whether it's the harness or not by checking if the 3rd brake light is working.

I say that because the brake light circuit is split. It forks off in the cab, from the driver's side, one branch goes up to the roof to feed the 3rd brake light. The other one goes out of the cab, down the driver's side framerail, then forks at the end of the framerail with one branch up into the driver's tail light cavity (behind the fixture), the other across the bumper and up into the passenger tail light cavity.

Logic dictates:

• If the roof-mounted brake light is working, but the tail lights on the bed aren't, you have an issue with your circuit somewhere between the cab and the end of the framerail where things split to feed the bed tail lights.
• If all three of the brake lights are failing, you have an issue farther upstream, like somewhere between the battery and the point (after the fusebox) where the wiring forks up to the roof and back to the framerail [OR] because your brake pedal switch is fucked.

 

You’re mixing up brake lights and tail lights here. OP says his brake lights are working.

 

Ah, hot damn you're right. Whoosh, right over my head.

In that case, @nphunter, "stupid check". Did you check to make sure you've got dual-filament bulbs installed?

 

I’m using 7443’s, they have two filaments in them and the lighting book says that’s the correct bulb.
Checked and I have 12V at the panel for the tail light. I’ll start looking at wires.

 

Ok, in that case, here's what you need to know.

If you pop out your driver's side tail light, the Green wire is constant feed for lights-on mode tail lights. Green/red stripe is brake light.

Inspect the green wire carefully after popping out the tail light. Test for voltage on the back of the connector when the lights are on, you getting power there? Check the socket closely, make sure nothing is dicked, the wire isn't spliced or cut in there, like maybe someone was fiddling with the wires.

Trace the all-green wire downward in its harness/loom. Check for any signs of tampering on the harness itself, extra tape, that kinda BS. Trace both ways on that wire loom, toward the tag lights/trailer hitch, etc.

 

I’ll upload a pic in a second but the only wire in my harness that has 12v when the lights are on is not connected to anything on the actual light. Maybe the incorrect year lights or something?

 

Do you have tricolor lights? (Amber, red, white)

Those are for older trucks and shouldn't be on yours (or my '06), and I'm not sure if the pinout is different, I'd need to reference the EWD. Got a pic of the housing harness?

If that's the right light, and it loses power on your DMM when you turn the lights off, then ... you just need to figure out what's not making contact to the tail light line in the housing.

 

It appears to be correct the colors match on the pickups harness as far as where the green wires are. The one I have with power is red. I’ll see if I can find where I’m losing power. I’ll try to check continuity to ground and see if is shorted somewhere. I tried unhooking the trailer light plugs and it didn’t make a difference.

 

Those are CAPA certified DEPO brand housings, those are about the best aftermarket you can get and should be wired correctly.

The wire colors I just gave you are for my AC, I just noticed you have a DC. I wonder if the wiring/colors are different for DC?

 

Are both tail light harness pinned the same where they connect to the rear chassis harness? If not, maybe someone has put the RH tail light harness on the LH, and vis a versa?

 

Good Q. One easy way to find out, pull both housings and check the pinout. I wonder if the one pin (I see empty in your 1st pic) is reversed on the driver vs. passenger tail light harness?

 

I just pulled all the electrical diagrams and will trace down the fault after work, there's on plug on the drivers kick panel and one under the drivers seat that the power goes through prior to going under the vehicle. Hopefully it's something in one of those plugs, maybe something was pushed under the seat and pulled a wire. I will update the post once I figure it out. Thank for the help.

 

Well I crawled all over under the truck with a fluke after the plugs in the cab all tested good. Ended up dropping the spare and found a broken wire where the harness splits by the fuel tank. I’ve worked 16hr days since Monday so it just been sitting waiting to be fixed but I plan on fixing it this morning. Hopefully that’s the only break.

 

As far as troubleshooting, I first used a 12v wire from under the dash and tested the tail light harness to verify all the lights were working properly. They were good so then I started testing the plugs inside the cab. I tested voltage but to verify the plug was good I used the same jumper and sent power to the frame harness. I was able to get brake lights and reverse lights to work but not the tail light. From there I pretty much knew it had to be a wire in the frame harness. I stared just under the cab and moved back a couple feet at a time where I could reach the harness and poked my fluke lead through the coating on the wire. I had power back to the tank but not behind the Y harness that drops wires toward the diff in the rear. I dropped my spare so I could access the Y harness and one side had power, the other didn’t. I pulled one side and felt like I had too much movement in the wire. I then pulled the front side and the wire pulled out about 2” from the end of the harness.

It should be a quick easy fix.

 

Good job.
That looks to be a green wire and it is indeed a green wire for the tail lights.
But I'd guess your license plate lights didn't work either?

 

They were all out, but are all off of the same green power wire. It was a little difficult finding the J38/J39 plugs. The drawings aren’t great and the plugs right above them had a green as well. Once I’d figured out the correct green feed it was pretty quick and easy to find.

 

I'm so glad the rest of us in this subforum have 2000-2006 Tundras

I would hate to deal with all the bullshit you latest-gen owners are struggling with. You may want to repost your comment over in the 3rd gen subforum, it may help one of your fellow latest-gen owners out down the road.

 

2020 is Gen 2.5. Post on that forum. Here is a link to what you seek.

https://www.tundras.com/threads/interior-fuse-box-location-and-information.3720/