Starts when key turned to ON

Last night driving my 07 Sequoia (4wd Limited, 182k) on the Interstate in rain, my dashboard lights flashed intermittently a few times like a loose connection and then went out. The Speedo, tacho, and all the other gauges work as do the lights for the seat belt, gear position, ignition, etc. The odometer is blank, and the lights in the analog needles and the background lights are off (can’t see the speed at night). The car also starts as soon as the key is turned to the ON position without having to turn it to the crank position.
It happed once before a couple of years ago, and I disconnected the battery overnight and everything was good when I reconnected the battery and had worked fine since. Now disconnecting overnight did not help either.
I’ve too many things that I can think of that could go wrong. Anyone with any helpful pointers, or experience with this issue would be a big help. Thank you for reading my long post.

 

It would help to know if you've ever had an alarm, either dealer-installed, or aftermarket. Some dealers quietly installed the SECURIKEY+ and KARR systems without telling owners.

From our community info thread, "Electrical stuff ... and keys" section: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

• These trucks usually don't have a ton of other electrical issues. Hidden corrosion inside the battery/alt cables happens. Sometimes, a couple thousand miles after timing belt changes, people will have startup issues because the crank position sensor wasn't properly tucked away and gets rubbed by a belt (pic), correct routing info here. There's also a similar problem with camshaft position sensor under the cam cover, where the belt will rub through (pics). There's the rodent issues mentioned earlier. Occasionally, water trails down harnesses into the ECM behind the glovebox (pics, pics), or the in-dash fusebox (pics & pics & pics) it happens a LOT. Many drain/vampire issues trace back to aftermarket add-ons whether the owner knows they exist or not - alarms as mentioned earlier, brake controllers, poorly installed trailer receptacles, those are some big ones.

While I'm tempted to believe you have a short in your ignition is the culprit, pay specal attention to the bolded fusebox bit up there, since it's hit so many people over the years, it's why we have so many pics of cases to share. I'd rule out water intrusion, especially if you're the kind of person who doesn't think it's important to fix cracked windshields, or if you've been victimized by the shit work Safelite is known to deliver.

 

Water. Make sure it's not getting into the cab and corroding your electronics.

 

What @KNABORES said.

 

Thank you for your responses. I don’t have any aftermarket stuff. I have the original Nav radio, and the original security system/key fob. I don’t have a cracked windshield, or suspect water intrusion. I’ve had a couple of rodent issues in the past where they once chewed my knock sensor wire under the intake manifold, and once some wires by the passenger door door-sill, but both were in the winter when the car was warm. It’s warm weather now (Atlanta) so I don’t think it’s the rodents. Moreover it happened while I was driving. I don’t have any starting problems either. It starts the instant I turn the key ON (even before it is cranked). I changed the timing belt 6 months ago, but again no starting or mechanical issues.

 

I’ll check first Water Intrusion that I’m maybe not seeing. I do have a sunroof. Anything in particular to check? The fuse box on the drivers side left by the feet? Should I remove the whole fuse box to check behind it? Looks good from the front.

 

Water intrusion happens frequently in the 1st gen. You don’t need cracks. And it’s often the main source of electrical gremlins, where circuits get fused together or separated.

That should be your #1 suspect. Look at the links I shared in bold. Seriously.

 

Yes. Remove. Unplug connectors. Look for green traces as shown in the pics.

 

Thank you, . I’ll check those and report back with any updates.

 

Definitely water intrusion a possibility.

Only because it was fairly recent do I recall the below thread dealing with basically same situation on an 06 Sequoia.

https://www.tundras.com/threads/06-...ion-and-no-lights-on-the-dash-cluster.156954/

 

Mine started in the on position as well, right after a bad windshield install... Never saw any water, but once it dried up, no more issues. I got a new windshield correctly installed afterward.

I also had window and lock issues but the dash was fine.

My first post on this site was about this issue.

Good luck

 

Like I said, it started last night when I was driving in the rain. It had the issue when I started this morning, and also when I drove to lunch. It stopped raining in the afternoon and the sun was out. When I started after work everything was back to normal!!
I am regardless going to open up the black grill between the hood and the windshield this coming weekend and make sure all the drains are free flowing.
I thank all of you very much in helping diagnose the issue, I’m convinced based on your experiences that this is a water ingress issue. Appreciate everything very much.

 

The cowl panel you're talking about has nothing to do with drainage at the firewall, and absolutely nothing to do with water entry on the driver's side of the truck. There is one cowl fastener on the passenger side that will leak water straight down into the blower motor, it's covered in the definitive leak thread. That one is notorious, and virtually everyone has it actively happening if they haven't updated or re-sealed that specific fastener, but that's not your issue with electrical weirdness.

Most water intrusion on the driver's side, which is likely your problem, is happening from one of 3 places, and I really should add this to the definitive leak thread:

• Coming from the A-pillar: Either from these four tab/trim holder holes on the A-pillar for the windshield trim, or from your door seals like this.
• Coming from the windshield: Either the outer frame of the windshield is rotten top or bottom, you have standing water at the top of the windshield due to environmental buildup, your windshield is cracked
• Coming from the firewall: Check to make sure the main wire harness grommet isn't popped out or ripped, nobody has punched a hole in the grommet to add wires, or drilled other unexpected holes in the firewall that aren't properly sealed

The core issue is this:

• Water enters at one of the three locations above
• That water, at some point, intersects with a bundle of OEM wires
• That bundle of wires acts like a pipe to carry water straight down into to the fusebox or lower wiring connectors
• You don't see any drips, because it puddles inside the connectors or inside the fusebox, so you have no way to know there's a problem
• Looking at the outside/front of the fusebox, you typically won't see any evidence of leaking

On the driver's side, when it gets into the fusebox, it looks like pics & pics & pics.

On the driver's side when it gets into some of the connectors it looks like this like this, and here's what's inside that smaller connector, here's what's inside the larger connector, and what those pins look like, they're totally rotten.

On the passenger's side when it gets into the ECU behind the glovebox, it looks like pics & pics

There are probably other examples of the damage, but those are the big ones, big three area. Two key points to have in your brain:

1. Water travels down the wire bundles, so look for wire bundles that are flowing downward in the dash
2. You may be able to squeeze or probe the bundles after rain events to check for water, those blue paper shop towels are great for seeing water

This seems like it's the #1 cause of stupid gremlins in these trucks, and it's most commonly happening due to leaks on the driver's side. I dunno if it's just because Google is steering more people with 1st Gen Tundra problems to this forum or what, but when I first got here ~5ish years ago, we were maybe seeing one weird case like this a year? Lately it's like one ever 6-8 weeks.

 

Ok, updated the definitive leak thread to add "dash leaks" section with a link back to that last reply covering what happens with dash leaks.

Hopefully it makes reference easier.

 

Thanks Shifty for the detailed information. Even though everything is back to normal, I expect it to surely reoccur in the next heavy downpour. I’ll follow your advice and try to chase down that leak before it damages my fusebox or any electronics. Thank you!