Weird tail light issue...

This morning while still dark I went out to my driveway and my tail lights and 3rd over the cab were on (red). No key in ignition, truck was off, doors closed, light switch in cab rolled off. Started the truck, ran it thru the gear selector, lights rolled on and off and hit the brakes. Killed the truck and same thing. Red still on illuminated on all 3 lights. Disconnected the battery just so I can try and find and answer without the plastic getting too hot. Thank goodness it was cold last night as the lenses were warm.

Any thoughts? Truck is 03 AC

Thanks

 

I have a ton of thoughts.

You know the brake pedal has a plunger somewhere along the pedal which is how the truck knows when you're pressing the pedal or not, right?

Beyond that, there's a little plastic disk the plunger sits on, and it likes to crumble. You'll find a shitload of cases of that on here using Search.

I guess I'd ask:

• Have you found any bits of plastic on the driver floor board in the last few days?
• Have you located the plunger for the brake light, along the length of the pedal, and verified there is a plastic pad intact?
• Have you futzed with the plunger on the pedal to see if pushing it in/letting it out will turn the brake lights off?

 

Thanks Shifty...I'll look when I get a sec....

 

Saw no evidence of plastic part on floorboard, and actually saw no plastic anything in the brake assembly. Everything appeared to be metal. But that doesn't mean anything. I'm not too auto smart. Anyway hooked the battery back up, started the motor, pressed the pedal a few times and now its off. Weird. I'll watch it to see if it keeps doing it.

 

I used the search. Here's one of a couple threads on the same subject, with the exact same title as yours, basically:

https://www.tundras.com/threads/brake-lights-staying-on.93538/

This is the replacement part, less than $2 from Toyota: 90541-06036

The plastic puck from the factory is blue, IIRC, and it goes here, it's necessary to set the proper height for the pedal switch. If yours is missing, that's your problem. Note the swoop of the brake pedal in the picture, and where the steering column goes through the firewall for reference.

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Yup, it's there. In tact

 

Have you done anything recently with the tail lights, like change bulbs out? "Upgrade" to LED?

Do you often park outdoors? Have you played with the pedal to see if there's any point you can pitch it so the light turns off?

Relay potentially stuck?

 

Nothing done to the truck for months. Haven't done new lights for the rears...all stock. I drive it once a week. Truck lives outside 24/7. When my wife gets home I'll have her hit the pedal while I watch. Thanks Shifty...you're always the 1st to offer help.

 

I try not to be

I would need to look at the EWD to figure out where the tail light relay is, and if there's one relay that trips the HMSL (3rd brake light) and the regular brakes. I'd assume it has to be on the back of the in-dash fusebox if it's acting on all three, but for some reason I have it stuck in my head my 2006 have a relay behind the driver tail light but maybe that's something I added with my DIR kit for backup camera.

Have you ever checked for water intrusion into the fusebox? (pics & pics & pics, it happens a LOT)

 

If they all were red, that is Stop Lights and not parking light is what I'm understanding ?
If indeed they are all red, the Stop Light circuit is fairly straight forward and suspect stop light switch....possibly dirty contacts or mal-adjusted. Anything other would require VOM(volt ohm meter) to check for + 12vdc before and after switch when it's acting up. More check points can be advised if that doesn't pan out.

 

I have had the little plastic pad that activates the brake switch fracture on several vehicles. It always caused all brake lights to be on all the time, since the switch controls whether or not voltage is passed on to the bulbs in the Stop light circuit.

So if that describes your symptoms, then I'm pretty sure the brake light switch is your problem. And usually the switch itself is fine, but the little plastic piece that the switch pushes on has broken, leaving a hole in the metal bracket.

From what I can tell from my year or two of lurking, Shifty is the man, and very generous with his time and efforts to help fellow FGR owners. But I believe that the photo posted in post #5 is actually the plunger for the Park Lock cable. There is another brake light switch nearby.

At least that seems to be what I've been seeing in the FSM. I've been researching how to adjust both of these, since doing the GX460 front brake upgrade and then following it up with the T100 master cylinder % booster upgrade. The M/C upgrade changed the brake pedal linkage geometry, and that affected the functioning of both switches. At least in my case, maybe I did something wrong in my DIY install.