Thread:

Tow/haul button broke on 2001 gmc 3/4 ton 2wd

Long story short....leavin the boat ramp sat. and go to push the tow button and she no light up. Leave for home sunday and its workin fine again. Stop in wyoming for some frosty adult beverages and it not workin again. Any ideas what to check? What exactly is the function of that button....does it lock the torque converter? What is towing going to do with out it.....just be extra hard on the trans? or??

No one eh....I miss Tom(impatient1) lol

Circuit Description
Tow/haul mode enables the operator to achieve enhanced shift performance when towing or hauling a load. When tow/haul mode is selected, the tow/haul switch input signal to the body control module (BCM) is momentarily toggled to zero volts. This signals the powertrain control module (PCM) to extend the length of time between upshifts and increase transmission line pressure. Cycling the tow/haul switch again disables tow/haul mode and returns the transmission to a normal shift pattern.

You'll have to install a scan tool and go through the diagnostic procedures:


Diagnostic Aids
If the electrical circuit tests are OK and the tow/haul shift pattern is not occurring, there may be a mechanical/hydraulic condition that prevents tow/haul operation. Start with a multimeter for diagnostics - check power to the button and work forward/backward from there. More than likely it's the button or wires in the shifter lever, or steering column, or where the shift lever and steering column meet that are bad. It's an orange wire in the column - 90% chance that your problem, and 95% chance it's where the column meets the lever. How good are you with a soldering iron and heat shrink?

Thanks guys....Sounds like a scan tool would be a bonus. Ran it to the store 2 days ago and it worked then....so apparently its intermittent. I thought maybe the indicator light was toast.....when the light wasnt coming on...there was no rpm change. Now that the indicator light is coming on I can see an rpm change, so sooo much for that theory. I guess next time its out I will try to get to a scan tool. Fock I hate electrical.