SOLVED: Partial brake lights stuck on issue

Post 14, looks like the red and yellow green rubber things are sticking out partially. Maybe those 2 were swapped by a previous owner.

 

Ended up having to work this evening so just getting back into these. Those little sealer plugs were out on most of the lights, I think they’d just worked themselves out, they’re not very tight after I pushed them back in.

That is a good idea on the multimeter, I’ll have to give it a shot. The wife’s going to love that time together

Agreed on color changes. Pure evil.

I’ll check those out again. Even though they’re OEM lights, I’m tempted to believe they’ve been messed with judging by the zip ties holding the gray connectors together, as well as the left side plastic retainer clip being broken.

If it comes down to swapping pins I guess I’ll have to buy one of those little pin tools. I tried several small tools I had to release them and couldn’t. That oughta be fun!

 

Be careful probing the connector. If you accidentally short 2 pins together a fuse could pop. Don’t bend the pins. Pulling the pins out isn’t difficult if you have the correct release tool. You could also cut & splice it back together correctly. I like to use uninsulated butt connectors crimped, soldered, then covered with heat shrink. You could also wait for someone to post a wiring diagram. Or buy new short harnesses, which won’t help if the pins were swapped in the connector they plug into.

This is what I use.

$68 OTC 4461 6-Piece Automotive Terminal Release Tool Set with Case

https://www.amazon.com/gp/product/B008PV8F30?ie=UTF8

 

Did a little probing with the multimeter this morning, with taillight side removed. Also checked any related fuses, with everything good that I looked at.

Headlight switch off, 12V ground to blue when brake is pressed.

Headlight switch on, only voltage present is constant 12V ground to green, regardless of brake pedal pressed or not.

I guess I’m going to run to O’Reilly’s and grab a stop switch just to see as @12TRDTacoma has suggested. Worst that happens is I’m out $25, and have a spare, and it’s be one thing to knock off the list of possibles. Still seems weird though.

 

Well, swapped the stop switch out to no effect. Got under the truck again, looking for anything out of place at all, and can’t really find anything. There’s a wire tapped into the trailer harness that looks like it runs to the air compressor, but when the trailer harness was disconnected it effected no change.

@TnShooter linked me the post with all of 2015’s diagrams, but I’m not knowledgeable enough to understand them yet to go any more in depth than being instructed what to do and replying with information.

There is a relay that I’m curious about in the main fuse box- STOP LP CTRL; I wouldn’t think a relay would burn out this young but I’m down to thinking it’s a headlight switch issue, a relay, or chasing ground points. . .

 

The brake light switch is working, or the 3rd brake light wouldn't work like it's supposed to.

I think you're going to need help there. Or bring it to a shop competent enough troubleshoot it. I'm pretty certain it's just wires got swapped, wrong bulbs, or possibly a short in a trailer connector.

Or if you can specify what you mean by the blue wire, theres 2. 1 on the female connector coming up through the hole. 1 on the short harness with the male connector. Same info needed for the green wire. Its confusing enough with wires changing color after the connector.

 

All wires tested were on the female truck side of the harness with the taillight portion disconnected if that helps.

Here’s a diagram that looks like it may help to someone competent:

 

From where I am sitting it appears that the Green and blue wires are swapped. The LED lights should not be effected by the headlight switch at all since they are different circuits.

Blue is for the stop lights and green is for the tail lights. Both circuits use the White/black stripe for ground.

 

Do a relay swap real quick. At least the brake switch has been ruled out.

 

Are there any relays in the box you know for sure would be a direct swap? I’ve did some base level relay searches on that one and coming up empty on a straight replacement by name. . .

 

You just gotta look for one that is the same size and make sure they have the same pin out. I don't know of one off the top of my head that is a 1 for 1 swap, but there should be one there.

 

I’m with him.

Green and Blue are consistent.
Green - Tail
Blue - Stop

This picture doesn’t look like it matches up to me?

 

And the black wire with a white stripe.... Ground?

 

There's your problem!

On the left taillight assembly, the one with the closeup plug photos, the red/white and the green wires are swapped at the connector. I assume the same is true for the right side, but I don't have a closeup of the plug to prove it. On the photos, I traced each wire to the backup light, stop/tail light, and turn light on both sides.

You only have to swap the red/white and green wires on each taillight. All the others are OK.

Pin 1: Left side: The solid yellow to blue/white connection is OK. Right side: Should be blue/white to blue/white. Turn.
Pin 2: Green on harness is right. Red/white on taillight is wrong.
Pin 3: The black/white to black/white connection is OK. Ground
Pin 4: Blue on the harness is right. Green on taillight is wrong.
Pin 5: Red to yellow/orange is OK. Backup

On both taillights,
the top row of wires should be blue/white, green, black/white
the bottom row of wires should be red/white, yellow/orange, empty

At the taillight, these are the correct wire colors. They all match the wire colors on your wiring harness, but not your taillight:
R5-1 Turn Left: Yellow
R6-1 Turn Right: Blue with a white stripe
R5, R6 2 Tail: Green
R5, R6 3 Ground: Black with a white stripe
R5, R6 4 Stop: Blue
R5, R6 5 Backup: Red
R5, R6 6 Empty
R5 is the left plug. R6 is the right plug.

Pin numbering. Male and female sides are mirror image. To identify pin numbering on the connector, find the empty hole. It's always pin 6.
1 2 3
4 5 6

Since half of the ten wires on the two taillights aren't the Toyota colors, I'd bet those aren't the original taillights.

My theory: The previous owner installed new non-Toyota taillights, probably to make the truck look better for sale. The new taillights came with the wiring mistake. They lit up, so the previous owner was happy and didn't notice the problem.

The swapped wires in the taillights explain all the symptoms. There is no reason to believe you have a problem with a ground, brake light switch, relay, or computer board. My information came directly from the factory 2010 Toyota Tacoma Electrical Wiring Diagram book.

Though that's where the mistake was made, I wouldn't try to remove and swap the wires in the connector. If I could open up the stop/tail part of the taillight assembly, and find the wires are soldered in there, I'd unsolder them and swap there. If soldering isn't for you, I'd just cut the wires and splice them with waterproof heat shrink butt connectors. The red ones are probably right. You'll need blue if they're too small.

 

I’ve got the terminal pin puller coming in a day or two, I’ll switch pins around and see if I can’t get it working right. Thanks for the continued assistance guys, hopefully that solves it!

 

Here is a plug Pin Diagram.
It might help make it a bit easier.

 

I'll second the previous poster and say check/inspect for bad grounds: Loose, corroded, rusty, broken wire. Remove them and clean/shine them up, including the area where they're attached to the truck. Start with the ones near the tail lamps themselves. Bad grounds can cause all kinds of weird problems, including turning on lamps that should not be on. I have seen this myself a few times over the years.

If you decide to do this, work on the grounds one-at-a-time and check each time so see if the problem is gone. If it is, you'll know the culprit. Good luck.

 

Soooooo the pin extractor came in a full day earlier(thanks Amazon).

I was out the door as soon as it showed up, and went straight to work. @Jerry Bear I followed your wire up chart, swapped the red and green wires on the tail light itself, and presto chango, I now have properly working brake lights!!

I did look inside the bulb housings at the idea of desoldering and resoldering them, but they’re terminals that would’ve been harder to deal with than the pins. In the end, the taillights are wired properly to plug and play should I change them out and someone else want them, so there is that.

A great many thanks to all of you guys that helped me troubleshoot this, especially @TnShooter, @Waasheem, @Jerry Bear, @Jimmyh for the wiring diagrams, tool recommendation, and cross help amongst yourselves to diagnose it, and to @12TRDTacoma for the suggestions that I wouldn’t have thought of just in case!

My hat is off to you guys!

 

I have the same problem after I changed taillights for some fleabay specials. I bet they’re the same way. So glad people take time to contribute to these threads…really take it for granted how easy it is to grab a solution.

 

Just verified mine had the exact same problem. Green and red were swapped. Was able to swap the pins at the “bulb” and not have to splice. I’m guessing most aftermarket Chinese replacements are wired like this right now.