Dash lights flashing

My buddy has a 2021 SR5 and maybe once a month, upon startup all the dash and warning lights blink like crazy and some of them continue to stay lit while driving (can’t remember which ones- but I don’t think that’s relevant- I saw it happen and it’s a lot of them).

Dealer says it doesn’t throw any codes. And it seems to run just fine. And then this “symptom” won’t return for many weeks or months sometimes.

I’ve searched and haven’t found anything similar. Any of you recall any threads discussing something similar in recent model years?

 

Electrical gremlins are the worst.

Makes most technician’s run for the door.

You would be surprised what a bad ground can do to an electrical circuit. Especially when computers are involved.

 

Yeah, I told him I think this might just be one of those things that won’t be resolved. He’s frustrated. New-ish truck and he feels like the clock is ticking on a larger issue.

 

It’s still under warranty? so he just needs to find the right Toyota tech that’s able to measure up to the task.

 

Finding a tech that is able to “measure up” is easy. The problem is they are not going to paid for their time, finding one that is willing to give up there livelihood is not so easy.

 

I would say for the owner of the truck to be prepared to take video when the issue occurs. Video evidence provides proof of the issue and when presented to Toyota the issue is documented and starts the clock ticking toward a lemon law claim if Toyota can't fix it.

I'm with @Slopemaster on this one. It is either a sometimes faulty ground that may just have a resistance reading too high occasionally. Or, it is a harness connector that is not seated all the way.

The engine bay harnesses should also be inspected for rodent damage.

 

I agree with the above suggestions of checking and verifying secure/clean battery connections to start with. Hopefully will be something easy to diagnose.

Also do a quick visual to make sure no rodents have starting feasting on the wiring.

 

Where did you hear that? That’s not how it works.

 

yeah, check for rodent damage. It’s also worth checking any aftermarket mods tapped into the system, lights, radios, or other doodads

 

No aftermarket add-ons.
We do have it on video.

 

I’m betting on some physical damage to wiring, rodents or otherwise. You would think it’s too new to have electrical problems due to corroded grounds or connections.