Tow/Haul light turning on when shifting gears.

First off, thanks you to everyone's help over the years. I have a 2004 Tundra DC V8 with 255K that I have owned for the past 11 years and my dad had for 7 years before me. These threads have been enormously helpful as I have done nearly all maintenance myself (and with dad early on).

There is an issue with the Tow/Haul light. The problem is intermittent and variable. The issue has displayed in different ways as described:

1. The tow/haul light comes on when shifting from P to D. Pressing the tow/haul button turns it off and the truck shifts to overdrive normally
2. The tow/haul light comes on when shifting from P to D. Pressing the tow/haul button turns off the light BUT tow/haul mode is actually on and the truck never shifts to overdrive. Pressing the button again turns off the light and tow/haul mode turns on (i.e., the light and drive mode or dyssynchronous)
   
3. The tow/haul light comes on when shifting from P to D. Pressing the button does nothing. I shift back to P and the light remains on. I shift to D while holding down the tow/haul button and the light turn off and the truck shifts normally
4. The tow/haul light comes on when shifting from P to D. I pull the gear selector towards me but do not shift gears. The light turns off. The tow/haul mode is sometimes in sync with the light or out of sync with the light as above.

All other dashboard displays work normally. All steering wheel controls function normally. The engine sounds normal and transmission shifts as it always has without any noises or grinding. All fluids are up-to-date and look clean.

I have disconnected the battery several times without any change.
I removed the paneling under the steering column. All connectors look to be fully attached and secure. I do not see any frayed wires. I was not able to remove the steering wheel paneling and did not want to do anything to jeopardize the airbag system.

I cannot find any specific fuse for the tow/haul button/mode.

Is this a sign of the computer or transmission going bad? Any one else with similar issues and fix?
Thanks in advance.

 

Checked tranny juice?

is your area moist?

 

Good morning. This may be a difficult one to diagnose over the internet. The Tow/Haul mode button electronically activates the over drive. It sends a signal from the button to the transmission valve body by way of a circuit through wiring, harnesses and the ecm. Most likely, you have a short somewhere. If I had to take a guess, that short is in your shifter column. I know that someone on here recently had an issue with their light and found the wire sheathing chaffed from years of rubbing against the gear selector as it moved up and down. The exposed wire grounded itself and caused a short activating tow/haul mode. I'll see if I can find the post for you.

 

All his issues do seem to arise initially from shifting. What’s weird is the different ways it turns off or doesn’t once erroneously triggered.

 

and it very well could be an ecm issue. I really don't want to throw a spit ball on this without anymore leg work (drag and pictures) from OP.

 

Where is this tow/haul button and light you speak of ?
Would you be talking about the O/D(over/drive) button on end of gear shift and the O/D off light on dash ?
If so, there is a known issue of the O/D button wire having it's insulation chaffing causing most of what you mentioned.

 

That's exactly the one I was thinking of

 

I see that now....it's early and didn't think anyone would be up to post this early like my dumb ass

 

Good morning

 

That’s my first thought wire chafing in the wire from the button in the shifter.

 

OP got me thinking that maybe the 2004+ actually had a tow/haul vs my OD on and off button?

 

My 04 DC LTD has the O/D button/switch on end of gear selector, as does the 05-06.

From 06 OM....

 

As I had previously assumed. But I have not owned a 2004+, so OP got me questioning things

 

You are correct. Over/Drive is the correct term. Not Tow/Haul. I should have caught that.

The video sounds like it very well could be the exact thing. If I get a chance after work this week, I'll take it apart and see what that wire looks like and post photos back here.

Thank you!

 

Tranny fluid is in the HOT zone while at operating temperature.

I live in a very dry area actually. Utah and Nevada.

 

Hot zone sounds bad. So you’re saying your transmission has been regularly overheating?

 

I believe that OP is referring to the dipstick

 

The Black Mamba is correct in that I was referencing the dip stick markings.

 

Duh. Makes more sense

 

This was the answer! If I had only searched the correct terms it would have been obvious. Thanks for putting me on the correct path.


I followed this video to install the new part: https://www.youtube.com/watch?v=lpXnxga5W4E

Toyota Part Number: 33055-0C020. https://www.toyotapartsdeal.com/oem...=LIMD;5=ATM;6=4HC;7=DCB;9=SD;0=UCK41L-PRSLKA)


I initially purchased a new shift lever through AutoHausAZ. Unfortunately, it did not fit. The base of the shifter was larger than the original. I considered taking an angle grinder to it but decided to just get one from my local Toyota dealer few more dollars. Install was easy and it works perfectly.

Thanks again everyone.