Brake lights not working and truck wont start.

Hey all,

My 2020 tacoma has basically bricked itself.

Here's some context;

Was out on a dump run with the trailer and was heading home. While slowing down at an intersection the dash lights up and i get the infamous brake override malfunction alert.

Truck drives as normal, all the way until I pull over and stop. Thinking, maybe, then trailer did something weird and a restart will clear the issue. Wrong.

The truck seemingly no longer recognizes the brake pedal and won't start. It turns on just fine, the electric works just fine, just won't send the signal to start.

So I run through the fuses and sure enough, the 10amp STOP fuse is blown. Great, easy fix. I swap that out and the brake override malfunction warning goes away. Double great. Go to start the truck...nothing.

So I try the remote start and the truck fires up no problem. It's at this point I notice the tail lights will turn on and blinkers work fine, but the tail lights are unresponsive to brake pedal input. Both when started with the remote start and with just the power on. Thhe third light doesn't respond to pedal inputs, but will turn on white for oen doors or when turned on using the switch at the dash. Same goes for the trailer lights, blinkers work but brake pedal inputs don't register.

So I'm kinda at a loss at this point. I feel like I may have narrowed down the issue to the brake pedal/switch and electric. But don't really how how to attack that system and rule it out as the culprit.

A little about the truck for you:
2020 trd offroad
Stock lights
No pedal modifications,
N2 designs Remote start(2 years old, no issues)
RSI smart cap, tied in through provided harness at the tail light. (Removing it from the system and returning to stock wiring doesn't fix the issue either)
Everything else is completely stock.


Any help would be appreciated, thanks.

 

Sounds like the Brake Light switch is loose or bad, given the blown fuse I'm leaning to bad

 

is it factory push button start?

 

Thanks, I'll dig into that.

Yes, factory push start.

 

@CraigF good call on the switch.

I pulled it out, and could see that the switch button was fully depressed and not returning to its fully extended position.

So I took it apart, got everything back in the correct position and boom, trucks starts.

HOWEVER. I think the switch issue stemmed from me fucking with it yesterday before I asked for help. But, If that switch wasn't the reason for the short.....I still have some gremlins in the system I need to hunt down.

Potential culprits are;
1.) The dead taillight bulb I found and replaced
2.) The trailer
3.) The wiring loom for the RSI smart cap. But I'm hesitant to blame that as it's seen months of of use and I can't find any problem areas with it.

 

my 22 can bypass the foot on the brake pedal start by just holding the start button for 10 sec or so and it will start

 

Curious, what were you doing with the brake light switch to begin with? Seems like a strange place to be, unless you had an issue.
Glad you got it narrowed down though.

 

Well. Shit. The more you know.

 

Well, when the truck wouldn't start, and I was waiting on AAA for 3 hours in 95* heat, I had time to troubleshoot and poke arround.

I've had a bad clutch switch send me on an electrical goose chase before, so the switch is the first place I checked when I realized the truck wasn't sensing the brake. In reality, I made it worse. It wasnt until this morning when I looked up the part that I realized i was partn of the problem at which point I reassembled the switch correctly and, well, yeah.

 

I had a 77 Chevy which the brake switch came loose several times on to the point it would illuminate the brake lights, though I believe the underlying issue was a huge stereo that vibrated it loose. I don't suppose you have something like that?

 

Just a WAG but I’d start at the trailer and go from there. Sounds like perhaps a short in the wiring started the whole kerfuffle.