HELP - Brake light issues

[christurnerrr]

Hey guys - sorry if this has been covered somewhere, but I searched for a while and couldn't find anything that matched the issue I'm having.

Was driving a uhaul behind the wife who was in the T4R the other day and noticed that there were no brake lights. Once we stopped again, I tried to trouble shoot. Top brake light works as normal. Neither tail light brake function works. All other lights in the tail lights work. Red running tail lights also work, so I know the bulbs aren't bad.

What could be causing this issue?? I've had no luck finding anything.

Thanks in advance.

 

[flyrv9]

Well depending on what year your T4R is, you could have a bulb problem. Bulbs with filaments (vs LEDs) use a different filament for the brake light. So tail / turn filament in the bulb could be good and the brake light filament bad. Granted it's odd that both are not working. A fuse should include the third brake light - but I'd check just the same.

Also, there have been threads involving issues with the tail light assy. They all center around poor connections in the crimps of wires in the socket. Apparently a bad design. Once again odd that both are bad. Time to get the meter out and start checking. Or if you're under warranty - take it in. Safety issue.

 

[christurnerrr]

This feels unlikely, but worth mentioning I suppose.

I recently tripped ABS/Trac lights when installing new UCAs and had to replace my ABS/wheel speed sensor harness on front passenger side. When I hooked up the new one, my lights went away.

Is there any way any of that would cause this issue? It's the only thing I can connect to a braking problem? Super bizarre

 

[christurnerrr]

Quick update: busted out the multimeter. I have 12v power all the way to the socket. Still no brake light. Could this be a strange socket problem?? Or bulb?

I'm baffled

 

[Bossman]

Brake Light not working - SOLVED!

BOTH brake lights not working. Anyone any ideas?

Brake light gremlins

 

[flyrv9]

Use your meter remove and check the bulb/s. On the ohms scale it should be close to a direct short. And, check that the bulbs are seated properly in the socket/s.

 

[Perfection]

Howdy folks. Reviving this thread with same problem, new twist.

2012 Trail Edition. So my driver's side brake light won't light up, center and right work fine. Both filaments are fine in the bulb, and the socket isn't the problem.

The problem is the blue wire feeding into the grey wiring harness that plugs into the taillight housing. I can wiggle it, and at times the brake light comes on, but I cannot get it fixed/working consistently. Can I purchase this specific harness from Toyota or elsewhere? Is there a part number or way to find it? Or do I have to pay the stealership to fix?

Thanks in advance!

 

[flyrv9]

Previous threads have indicated the wire crimp of the socket contacts to be the problem. Can you determine where the wire is bad? If so, splicing in a new section should fix it.

 

[Jivewalker]

Howdy folks. Reviving this thread with same problem, new twist.

2012 Trail Edition. So my driver's side brake light won't light up, center and right work fine. Both filaments are fine in the bulb, and the socket isn't the problem.

The problem is the blue wire feeding into the grey wiring harness that plugs into the taillight housing. I can wiggle it, and at times the brake light comes on, but I cannot get it fixed/working consistently. Can I purchase this specific harness from Toyota or elsewhere? Is there a part number or way to find it? Or do I have to pay the stealership to fix?

Thanks in advance!

Glad to see another 2012 TE! I haven't had that problem but i know what you are talking about. I have worked on wiring harnesses before and I would bet that you can fix it with some patience and research on how to undo the harness without breaking it. I say go for it yourself. If you fail and don't have time to keep trying, then I would bite the bullet and go to the dealer, assuming it's one that you trust.

 

[Perfection]

Glad to see another 2012 TE! I haven't had that problem but i know what you are talking about. I have worked on wiring harnesses before and I would bet that you can fix it with some patience and research on how to undo the harness without breaking it. I say go for it yourself. If you fail and don't have time to keep trying, then I would bite the bullet and go to the dealer, assuming it's one that you trust.

That's awesome, mine is also black. We call her Black Betty. 190k and rolling.

I was able to find a part number on the harness, really tiny writing, it's 6-pin 90980-12349. The blue wire doesn't appear to be damaged and that it's just a loose connection in the harness. Tried pushing it in and adding some dielectric grease. Now it won't work period. I guess I'll try buying the harness and replacing it.

 

[Nick B]

Any updates ? I have the same problem with my 2010 TE .
Being a safety issue I’m surprised there isn’t a recall or at least a technical bulletin out on this .

 

[ElectroBoy]

That's awesome, mine is also black. We call her Black Betty. 190k and rolling.

I was able to find a part number on the harness, really tiny writing, it's 6-pin 90980-12349. The blue wire doesn't appear to be damaged and that it's just a loose connection in the harness. Tried pushing it in and adding some dielectric grease. Now it won't work period. I guess I'll try buying the harness and replacing it.

Just a PSA:
People seem to have the wrong idea about “dielectric” grease. It is not conductive. It’s a silicone-based grease that has properties that can withstand high temperature, and is an insulator. It’s a lubricant that won’t damage plastic or rubber parts like petroleum jelly will. When you fill connector pins with it, like in your trailer brake light connector, and re-install the mating connector, the metal pins are tight and they squeeze and displace the grease at the metal interfaces. And a little bit of metal is also displaced. The electrical connection is made and is surrounded by a protective layer that keeps out moisture and air, thus no corrosion.
What you did was the wrong application. It’s really hard to clean the grease out. You will have to replace the wire and connector pin, maybe the whole connector would be easier.

 

[djs239g]

Any updates ? I have the same problem with my 2010 TE .
Being a safety issue I’m surprised there isn’t a recall or at least a technical bulletin out on this .

..Had the same issue with my 2010 SR5 T4R brake light…only on driver’s side.
The ‘Stop’ fuse under the hood and the bulb itself were both good.
All I did was wiggle the blue wire on the 6-wire small harness and now the brake light is working. If it goes out again I will try some dielectric grease on the contacts..saw that stuff when I bought new brake bulbs (that I didn’t need) at AutoZone.

…so a big thank you to whoever posted the tip about wiggling the small blue harness wire!

 

[Humble Leader]

..Had the same issue with my 2010 SR5 T4R brake light…only on driver’s side.
The ‘Stop’ fuse under the hood and the bulb itself were both good.
All I did was wiggle the blue wire on the 6-wire small harness and now the brake light is working. If it goes out again I will try some dielectric grease on the contacts..saw that stuff when I bought new brake bulbs (that I didn’t need) at AutoZone.

…so a big thank you to whoever posted the tip about wiggling the small blue harness wire!

My 2010 RX350 had a similar issue with the daytime running lights. they would go on and then off and I couldnt figure out why. first drivers light then passenger. wiggling the wires solved the problem so I bought new plugs and cut the old ones off and replaced. now they are working fine. I wonder if after a while the wires get strained or stiff or corroded and don't make good contact in the connector. I would say thats the first non wear and tear item I had to replaced on that vehicle in 16 years ha