2024 Tacoma WEIRD Electrical Issues - Help!

[TacoDallas]

Hey all, I have a 2024 TRD Offroad Premium AT. Recently, at startup the lights for the fan speed and etc... start bright but dim to nothing as well as the following issues at the same time :

No wipers except on ultra high speed
Tachometer shows zero even when driving
Dome lights do not work
Turbo gauge gets stuck
Radio display in gauge cluster goes blank
Fuel gauge "KM to empty" gets stuck and reads incorrectly

This all eventually starts working again at varying times once you drive for a while. It all seems to start when the truck is first started and then all comes back slowly.
The dealership just did all 3 recalls and could not see any codes. Of course it would not do it for them but as soon as I brought the truck home it all started again.
Any ideas?

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[RedTacoma26]

Based on your description, I would look at the battery first. After startup the voltage maybe low and as you drive it the alternator brings the voltage back to a normal level. This might explain why things start working as you drive it.

 

[djevans]

I'd consider starting with physically checking, tightening, (maybe removing them, sanding, and retightening the connection point) every ground connection point on the vehicle. Remember though, you're under warranty I suspect. (You don't want to do anything that would void the warranty(but you could check to determine if they are secured tightly) I don't have a list, but you will have more than a single battery negative to frame in most cases. "Generally," the battery negative lead attaches to the engine, then other bonding grounds like engine to body, maybe body to dash, even under the dash, I've found them everywhere. I haven't worked as a mechanic since 1974, so a lot has changed but not grounds. They need to be perfect. Finding no anomalies with the grounds, start looking to see If there are any common connection points for the items that are failing. Did you have any dash work done? Maybe some other work? I've found bonding grounds left off or loose from former repairs. This can be really tedious. Check as many plug sets (connectors, for being loose or even corrosion) as you can reach. Call Toyota. You've got to be under warranty, so maybe just keep taking it back. Leave it with them. Let them drive it for a week or two. One more thing... I keep a USb volt meter plugged in to every vehicle I ever own. It finally paid off this week as a matter of fact. My wifes' 2026 LEXUS RX350 Luxury battery charge voltage became erratic. I then had a "BATTERY DEFECTIVE" message pop up on the screen after a few days. It's at Lexus right now. Lexus seemed to know immediately and felt it may be related to a firmware update.

 

[Solar Octane]

Bump. I'm experiencing the same issues as OP. What was the culprit?

 

[TacoFreak]

Bump. I'm experiencing the same issues as OP. What was the culprit?

Did you recently have any recalls done?

 

[Solar Octane]

Had a software update for one of the recalls about 5 months ago. Had my 20k inspection last week. The issue started 4 days ago. Same as above:

No wipers except on ultra high speed
Tachometer shows zero even when driving
Dome lights DO work (different than above)
Turbo gauge gets stuck
Radio display in gauge cluster goes blank
Fuel gauge gets stuck and reads incorrectly
Left headlight goes out intermittently
Outside temp gauge does not display a number, just F

Same as above - it will all start working again at varying times while driving. Sometimes cutting in and out.

 

[TacoDallas]

Had a software update for one of the recalls about 5 months ago. Had my 20k inspection last week. The issue started 4 days ago. Same as above:

No wipers except on ultra high speed
Tachometer shows zero even when driving
Dome lights DO work (different than above)
Turbo gauge gets stuck
Radio display in gauge cluster goes blank
Fuel gauge gets stuck and reads incorrectly
Left headlight goes out intermittently
Outside temp gauge does not display a number, just F

Same as above - it will all start working again at varying times while driving. Sometimes cutting in and out.

Finally, someone with the same issues. As soon as the weather warmed up all issues went away. It seems to only be a thing when there is a lot of moisture in the air or the temperature is low. Dealership thinks I’m nuts….

 

[Mercedes]

I'd think if the problems were the result of software, it'd be easier to identify a trend or make it easier to repeat?

It would be a good idea to check the battery and the charging system. It'd clear those areas and might offer tells of problems elsewhere.

I'm sure Toyota has something similar, but Ford has a diagnostic software tool they use in t-shooting. They simply hock-up to the On-Board Diagnostics port in the cab. Once booted up, they can then see each electronic module in a vehicle, confirm those are connected, talking and each has the latest software build. Checking all modules could offer some insight, either of a failing item or problem location.

I'd consider starting with physically checking, tightening...every ground connection point on the vehicle.

I was thinking something similar. Check for grounds and connections used which distribute power throughout the truck. There should be several.

As soon as the weather warmed up all issues went away. It seems to only be a thing when there is a lot of moisture in the air or the temperature is low.

That the issues went away when the temps increased makes me wonder if it is a loose chassis ground. There'd be the connection from the battery's (-) post to its end point, but there are other ties involving the engine, frame, inside the cab, etc. I wonder if one of those has worked loose. An increase in temperature would help close the gap.

That the problems occur in cooler temperatures make sense. If something is loose, that gap will open up when the temperature is lower.

Normally, moisture and water produces shorts, effects of which can be as you described. Some vehicles will have issues when water is entering the cab, like in the rain or after a wash and with a poor cowl, window or pillar seal.

If there's a stretch of cooler weather, maybe schedule with the dealer and leave overnight. As they arrive in the AM when things are coldest, the issue might repeat.

For the moisture, have the dealer run a hose across front door windows, windshield, cowl, A-pillars, hood. Low to moderate pressure, like in the rain or at a car wash. After a few minutes of that, focus on the inside, looking up in the dash, pulling the carpet and kick panels back to see if water is entering anywhere.

Most of the items under hood are covered, but give a visual check there for any loose ground connections, terminating connectors at the fuse blocks.

There's a fuse panel in the area of the glovebox. I'm still studying where the Body Control Module (Toyota might call it something else), the main in-cab computer is. But ask them to check around that and the fuse panel area, that those are staying dry and any connectors are seated well. All the problems you describe could be associated with a BCM, a connector to it, problem inside it, water intrusion, etc. Once things dry out or warm up, everything works as expected.

Edit,

In most modern vehicles, there will be at least two computers: a Engine Control Unit / Powertrain Control Module and a Body Control Module.

The ECU/PCM, under hood, controls the drivetrain while the BCM, in-cab, covers infotainment, external connections (cell, wi-fi), A/C, turn signals, instrument cluster, etc.

Multiple network segments (the Controller Area Network) will connect everything. Techs will access the CAN via the On-Board Diagnostics port, located immediately below the steering wheel.

- Battery and charging system
- Electrical grounds
- Water Intrusion
- Body Control Module

Given the choices and the OP's symptoms, while I'd check all four points, I'd be interested in clearing the BCM, connections to it, the area around it, first.

 

[IDontWorkForTheWaterCo]

Potential rodent damage?

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