Super weird problem - lights staying on with car off, headlights off, car locked?

Hey guys, my 01 started acting very funny recently. Occasionally, without any correlation with anything as far as I can tell, the running lights, cigarette ports (sometimes), and dash will suddenly turn on for a few minutes to a few hours, and then shut off as randomly as it started. I initially noticed it when my phone would Bluetooth connect to my unit powered off of the cigarette lighter when I was sitting inside my house, but chalked it up to a weird glitch until I discovered the car's lights were all on.

When this happens, the car is:
-off, with the ignition all the way to the left (it beeps when it isn't all the way over) and the key removed
-parking brake engaged and in park
-doors are all closed (door ajar light works fine)
-locked or unlocked (no difference)

As soon as I start the car the running lights shut off and everything goes back to normal, before turning the car back off again leads to the same weird condition immediately.

I have no idea what this could be, like at all. My guess is some sensor somewhere is busted, but I don't even know what it would be. Does anyone have any thoughts?

 

Here are a few similar threads. There may be more...try that "search" thing

https://www.tundras.com/threads/2006-sequoia-dash-lights-stay-on.123088/

https://www.tundras.com/threads/200...after-key-off-engine-off-–-work-around.75413/

https://www.tundras.com/threads/truck-is-off-but-headlights-more-stays-on.102575/

 

Check your in-dash fuse box for water. I would almost guarantee you have a windshield or a-pillar leak pushing water into the fusebox. It’s very common. So much that imside the electrical/keys section this thread: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

You will find several links to examples others have found, like pics & pics & pics, it happens a LOT.

…. And you’ll probably want to have your windshield replaced, so you can understand why water is coming through.

If you had the windshield replaced within the last couple years, guess what? You probably got screwed. If your windshield is cracked anywhere and you failed to repair, guess what? This is your punishment for not fixing it

 

@shifty` is most likely on the right track. But one other question in worth asking: Do you have an aftermarket remote start/alarm system?

 

Totally, I definitely missed that. I'm still surprised by how many people have told us they didn't have one, only to get under the driver's side dash and find evidence of either (a) spliced wires, i.e. there was an alarm, (b) remnants of an alarm, or (c) a full-blown alarm. Sometimes stuffed behind the driver's side kick panel, if the dealer installed it before the 1st person bought it. But anyway...

Only reason I'm leaning hard into the fuse panel leakage is because the integration relay/fusebox has a board that covers multiple fused circuits, and what he's describing is impacting multiple circuits, i.e. dash lights, running lights, cigarette lighters are all on separate circuits that pass thru the integration relay. Alarm would tap into the first two, incidentally, but not necessarily the cig lighter circuit.

 

This was the mess I pulled out of mine. I could hear an occasional click, like a relay, when driving. Was afraid it was gonna kill the starter when I was 20 miles up a forest service road at a trailhead.

 

This is exactly why I have yet (and may never) attach my aftermarket keyless module to any other wires than it's power source. I would love for my marker lights to brink and my horn to beep when I press the lock / unlock.... and then I see and read stuff like this. Nope, not for me.

 

I attached mine to my marker lights, but that's it.

 

Update: I have pulled every single fuse, relay, anything I can think of. None of them turned anything off when I pulled them, the parking lights and the interior lights just stayed on. No aftermarket alarm system either, although some aftermarket light pods and stuff which I unplugged all of them.

-each fuse in the driver's side kick panel fuse box
-each relay under the hood, including the headlights one
-drl resistor
-drl relay below the climate controls

Next step is to remove the kick panel fuse box, I think. I can't quite get to the nut that's way up there holding the top of the fuse panel on, any ideas?

 

Paging @daveeasa and @Mr.bee and @RUSTYNUTS for tips, they've all three done this.

You may be able to confirm water intrusion just by popping out connectors plugged into the rear, one at a time, and inspecting the tips (just the tip) for any green discoloration. Water + copper = copper oxide (which is green).

 

They actually look clean, and there's no signs of water damage to anything. I pulled the lowest relay and it and the slot look totally fine. Ignore the fact that I took a creepy photo of myself to show the terminals.

 

I think i used one of these hex drive sockets in a screwdriver.


i dont know it the sequoias is the same as the tundra but it helps to find a pic like this to help guide your hands while unplugging & plugging.

 

I’m talking about the actual molex wire connectors. If you look at the pics linked in the mega thread you’ll see what I mean.

The problem is, water streams down the wires, specifically, and puddles up at the wired connector sockets, eventually soaking inside. What you see on the relays means nothing. And it may only be one molex wire connector at the back of the integration relay (aka ‘fusebox’) that’s guilty.

 

Parking light fuse is in the cab. You’re 100% sure you removed that and yet your parking lights are still on? That should not be possible without some sort of short that’s really bad.

 

I could see a problem where there is intermittent contact between the ignition trigger and some constant wire causing the truck to behave as if key is in the ignition when it isn’t. Or possibly a short in the keyed ignition cylinder itself. But this theory doesn’t explain circuits still alive after their fuse is removed.

 

Yeah, I dunno what kinda crack I was on, but the TAIL and PANEL fuses kill power to the parking lights and the dashboard/center control lights, respectively. The short isn't *that* bad.

From a little more testing, I've determined that something about fully power cycling the car - like engine on and running and back to stopped - resets this issue. While the truck is off, if at any point I a) switch the headlights to first click or second click or b) press lock or unlock on my key fob, the lights/dash turn on again.

I have a haynes manual with all the wiring diagrams, I am going to dig through and see of I can find what hot wires lead to both those fuses. It almost certainly has to be ignition related, and I'm not confident it's a short either because those lights do turn off if the car is fully on. My guess is that I'll trace it back to a common relay that's somewhere behind the interior fuse box. The hunt begins now.

 

Inside the fuse box is basically a big f’n circuit board. Popping it out and cracking it open may show you what you need/want to see. I agree, the behavior describes makes it sound like a relay. But it could also be a bad trace on the board (due to crack in trace, corrosion, or otherwise)

 

Looks like the PANEL and TAIL fuses are fed by the taillight relay. Is this relay located behind the fuse box in that big circuit board? I've seen conflicting results online, with some saying it's actually in the tail light and someone else saying it's hiding up in that fuse box.

 

Found it. Back left of the fuse box. Will pull and test.

 

Pulled relay and tested it. I can hear it click and it applies continuity as required. Defintely the taillight one because they don't work when turned on.

FSM says to test potentially the door courtesy switch, and ignition switch next. I don't see any signs of corrosion or anything anywhere, everything is super dusty and no blue copper anywhere. Any other ideas?

 

Tested ignition switch, all good.

So to summerize: taillight relay is good, taillight switches are good, no visible corrosion or water or anything. Fuses kill power to respective systems. Power cycling car resets lights but doing anything that triggers the lights (hit switch, lock/unlock car, etc) makes them stick on.

It seems like the problem is narrowed down to either a weird short that acts intermittently and predictably between headlight switch - BCU or BCU - taillight relay, or it's the BCU. Specially, the B6-5 pin (which controls the taillight relay) is reading LOW when it should be reading HIGH (LOW triggers relay to be hot, HIGH turns off relay). I've had no other electrical issues with the car to speak of, so it's odd that this would be the single problem that I have. My fear is that this is the canary in the coal mine and I'll have further problems with lighting and such, but we will see. For now, I'll probably put these lights on a separate switch or tie them into the ignition or something. If nothing else happens, cool I guess. If I have a single new electrical problem, that $55 fleabay BCU is getting bought and put into the car.

 

This is another one of those times where I wish @BubbaW was still around. He had a gift for being able to see sense in this.

And I’m still suspicious of water damage inside the integration relay ("fuse box"), but 100% open to being wrong. Just because the relay is working doesn’t mean the circuits inside the box are OK.

 

Id swap the integration relay just to see if that did anything. It’s not excessively expensive and it’s a straightforward troubleshooting step. It may well not change anything but even that tells you something about where the problem is based on where it isn’t.

after that I’d attack and dismantle the engine bay fuse box and review everything inside it wire by wire.

but the ROI vs LOE sucks. I’m the same way with my airbags. Considering just pulling the entire system.

still, kinda nice to have the truck working as originally designed.

 

Welp

The problem fixed itself

I learned something. About myself, that is. About tundras? Not so much.

Maybe I'll go learn about what's at the bottom of a can of Rainer tonight.

 

If it comes back after a water event, let us know. Within a day or two of hitting a car wash, driving thru a rain storm, you know the deal.