Interior Electrical issues - ‘06 DC

Hello all,
New member, first post. Hoping someone recognizes the symptoms/clues and can point me to a solution.

Just bought an ‘06 DC about a month ago, and I’m experiencing an electrical puzzle that has me stumped.
Here’s the rundown of the symptoms and impacted functions: the truck has an aftermarket (Sony) radio which worked fine initially, but about 2 weeks ago lost power, along with the clock and the rear windows. It died gradually, over a day or two, and I watched both the clock and the radio act as if there was a loose wire making/breaking contact, until eventually neither one worked.

My first guess was a bad/loose ground, but the rear windows being involved does not make sense to me, as I would not have thought the windows would share power or ground with the radio or clock - When I try to operate the rear windows there is a soft ‘click’, like the sound a a relay makes, coming from the back of the cab. Maybe the low current side of the window operator shares power or a ground with the radio and clock?
While the radio and clock were in the process of dying, the ‘cruise’ indicator light would flash, although cruise control worked (and still works).

I pulled the radio and the wiring and connectors all look fine, and wiggling/shaking wiring and connectors going into the radio did not reveal anything. I’ve pulled and visually inspected all fuses (under hood and in cab).

Does anyone recognize these specific symptoms? I’m prepared to dive into the EWD, but really hoping this is a ‘known’ glitch that someone can point me to the most probable cause.

Thanks for any advice or input. For context, I’ve been driving and working on Toyotas for years, most recently 60-series landcruisers.

Pete

 

Sounds like one of two things to me:

1. Your truck had a dealer-installed security system like KARR or SECURIKEY+ and it's failing.
2. Your truck had water leaking into the integration relay (in-dash fuse box) either from the windshield or the A-pillar

Both of these happen frequently on 1st gen trucks. When they do, it tends to cause havoc across door locks, windows, and other interior-powered things, sometimes headlights and foglights.

 

Thanks Shifty, this is helpful.
I don’t know if the security system is anything more than stock; as for water getting to the interior fuse box, that is obviously possible, although I did look for evidence of this and saw none…but I will look again. This sounds plausible based on the way things went out, in a gradual/intermittent way.
Another frame of reference, for what its worth: the truck came from Alberta (dry climate) and is now in Ontario (much more humid/wet climate), and my gut says that this is a water/dampness issue.

 

Is it just the radio and clock? This sounds weird, but check the dome light. The metal connectors can get too close and cause random intermittent electrical issues.

 

I will check that, thanks for the tip

 

This is what I'm talking about with regard to water intrusion. There are a couple other cases I could link up, but this is the worst, thus the best, example.

https://www.tundras.com/threads/02-tundra-electrical-problems.45605/#post-1174202

 

I had odd electrical issues after a bad windshield install. Sometimes the doors wouldn't lock, windows acted stupid and the most scary was turning the key to ACC and the truck would start! All of this and I didn't see any water on the inside of the truck. So yeah, take a real close look before ruling out water intrusion...

 

Thanks again @Shifty for pointing to the most probable cause of my electrical woes. New box is ordered. $600 painful dollars to get it to the door (Canadian dollars - the exchange rate sucks right now).
My only question is Why TF do car makers not better protect critical computer/electrical parts from moisture (liquid or humidity)!? I had a Volvo a few years back that suffered water on the main ECU/computer due to the sunroof drain dumping water on it when it became clogged, and the placement of this critical part in the Tundra is not in the most protected place it could be.

Most probable leak point was the windshield trim mounting clip holes in the A-pillar.
Toyota can engineer some amazing mechanicals, but they sure don’t put the brightest minds on seemingly simple stuff, like not creating penetrations between inside and outside, where water will find its way in, and then place a critical electrical component directly underneath said holes (A-pillar clip holes leaking onto the fuse/junction box, cowl trim clip holes above the HVAC motor…I’m sure there are others). Seriously dumb.

Rant over.
Pete

 

Well, I guess that 'splains it...

 

Couple things here:

I'm sorry I was right, because a few of us on here know, that MF'er isn't easy to get out. I'm sure once you saw the rust/water mark where it bolts up, you knew exactly what you'd find after unplugging stuff. Bummer...

BUT! Silver lining here. You very easily, and very clearly found the problem without having to dig into every-goddamn-thing, y'know?

And yeah, I really don't know why these things aren't better protected from water. The leak in the cowl on these trucks is a "classic" that happens on a number of vehicles, hell, my last GM truck had nearly the exact same problem.

Stupid part? The ECU on these trucks isn't protected either. And it's in a clamshell, sealing it would've been as easy as using a rubber ring that might've cost a penny?

Loop back with us after you get the new integration relay installed, just to confirm all is working.

 

At long last the truck is back on the road and running perfectly.
As an added precaution to this ever happening again, I packed silicone grease into the joint of the clamshell housing, and into the gaps around each wire in each harness socket, and dielectric grease into the pin slots of each socket. It is now 99% waterproof.

 

Awesome! Appreciate the follow-up, and stoked you're back up and going again.

Bet you're even more stoked you found the forum!