Electrical Gremlins questions 2011 Tundra

I have the following electrical gremlins on my truck and want to see f anyone else has experienced it and found a fix for it or if someone may have the knowledge of where to start.

1 - I can fill my gas tank up, to full. Gauge goes to 3/4-F.
Stays like that maybe 15-30 minutes or a day or so, then drops down sometimes to almost E and the gas light comes on.
Distance to Empty at first will show between 280-300 miles. When the light comes on, sometimes it stays like that and sometimes it goes to just a few miles left.
Next day & even sometimes next start up, gauge goes to 3/4-F. Sometimes it stays on E.
Question - Could this be the gauge in the cluster or the sending unit in the tank?

2 - Radio always on dim, as if he lights were on, but they are off.
Flicking the lights on & off, will make if flash back to bright but always goes back to dim.
Question - Could this be the light switch/signal lever on the column?

3 - Turning on the left blinker, radio light blinks in time with signal, AND, both top and bottom left tail lights blink.
Right blinker acts normal.
No radio flash and only bottom tail light blinks.
Question - Once again, could this be the light switch/signal lever on the column?

 

Factory radio? Or aftermarket?

 

^ This, and if it is aftermarket, did this start after the installation.

Also;
Did you buy the truck new or used?
Did the radio and blinkers issues just start of the blue, or has it always been that way?

I have no idea about the fuel gauge issue unless something isn't grounding properly and it is causing all your issues...

 

Factory radio.
Bought used a few months ago.
The fuel gauge gremlin was doing it when I bought it.
The light Gremlin just started today as far as I know. I've never seen it before. But here's a funny. I just got in the truck started it without moving. The radio lights worked fine and the signal lights worked fine. No issues there. But I did watch the fuel gauge go to half, about where it should be with when I last filled up, and then slowly started going to quarter and then slowly went back up to half and then fell back down to quarter then went back up to half where it stayed.

 

That's odd, there should be no connection in the wiring between the tail lights and the radio.
Even more odd that it only happens on one side..

You may have a sending unit issue with the fuel tank.
Hopefully someone that knows more than I (it wouldn't take much) will chime in..

 

I would check to see if somebody installed an aftermarket radio, then swapped the factory radio back in before selling it. Some people hack up harnesses to save $17 on an aftermarket wiring piece. Next thing I would check is for a bad or incorrect ground. Generally speaking, the ground is usually the black wire; but in ToyotaLand, the WHITE wire is the ground wire. Might need to do some investigating there.

 

Another vote for a possible ground issue...

 

Yeah, the more I think about it, it is possible a grounding issue.
I'll put it on my rack this week and walk around under it grabbing ground wires. Then I'll move to under the hood ground wires.

The factory to aftermarket radio and back is a thought, but I had to clear bluetooth phones out of the factory radio so I'm thinking maybe not. But it's a thought.

But to go from working to issue, back to working all within a day is possibly a loose ground.

Thanks for the info guys.

 

Let us know what you find.

 

I Have a 2011 and had the fuel gauge issue. Mine would stop reading at a quarter tank sometimes, ran out of gas once thinking I was getting really good gas mileage. Replaced the sending unit in the fuel tank and it fixed the problem. Dropping the fuel tank is always fun, not too bad just make sure all your lines and wires are disconnected.

 

So, I haven't had anymore electrical issues until this evening, and I haven't had a chance to put it on the rack to look for loose grounds.
Being it was dark outside the blinking issue REALLY stands out and is totally odd. With any exterior off, the left signal on, the inside lights on dash alternate flashing with radio and 'INFO' display on top of dash. Radio and 'INFO' display are dimmed like the lights are on outside. Also, ALL of the rear lights, except for right reverse light, and the front signal and marker lights flash.
With any exterior on, only rear left signal light flashes, not the front left signal light.
Right signal does not affect interior and both outside lights flash correctly.

How do I upload a video? Looks like I can only upload pics.

I'm wondering if this could be related to the flasher module????
It's a $60 gamble to replace it and it not fix the issue.

 

Mine goes all over. Never sets in one spot.
Guess I'll be changing the pump and sending unit setup.

 

Does it matter whether you get the fuel sending/fuel pump assembly for a FLEX fuel truck or regular gas truck? Mine is flex fuel. I don't see where it would matter though?

 

I actually have no idea about that. Mine is just the regular gas 5.7 non flex.

 

Just to clarify, I only replaced the sending unit which is a simple clip on the side of the whole unit. I'm sure it makes sense to just replace the whole unit as your already in there but I hate replacing parts that are still working. And I wouldn't mind too much dropping the tank again for that. I'm pretty certain the sending unit is the same for flex and non flex, just not sure about the pump.

 

Oh wow, I haven't seen a part number for just the sending unit. Where did you find it?
I agree with the "If it ain't broke, don't fix it" thing.

 

Yes here's the link.

https://www.toyotapartsdeal.com/oem/toyota~gage~assy~fuel~send~83320-0c080.html

Part number is 83320-0C080 in case the link doesn't work.

 

Thanks, I don't know why I didn't see that before on my Toyota Parts site. Just old and blind I guess. LOL
$90 sure is high just for the sending unit though.

 

Though it’s less than a quarter of what Toyota wants for the whole assembly.

when I have multiple electrical gremlins I generally like to check the battery voltage under load, then the fuse box’s, then if that’s not the issue I check the grounds. I’ve had ants in fuse boxes wreak havoc as well as corrosion from water intrusion. Sometimes you can see the issues pretty readily.

 

I agree with Zapp.poor voltage and Bad grounds can cause multiple issues. My issue was a bad sender. Just a single issue.