Tow/Haul not engaging

[The Beast 6.0 liter]

I have a 04 f250 Super Duty and I start my truck and have my trailer hooked up, I push the tow/haul button on the shifter, the light doesn't come on. I drive the truck and it isnt engaged. I put it back in park and wiggle the shifter around and then it will engage. Does anyone know what can be the problem.

Thanks for your help

[ipz2222]

If it's like the older 4r100,s, the shifter has a set of wires that go thru the center of it. They are bad to rub into or just break from flexing. Replaced one this week that was broken.