Tow / Haul Button Not Working '05

Anyone have problems with their tow / haul button?

When my truck was new it worked like this. When I pressed the tow haul button, nothing would happen until I pressed the brakes, then it would downshift (or come out of overdrive) and hold that gear. This was great for going down hills, etc..

About a week ago, this completely went away. The light still comes on, but when I hit the brakes or do anything, nothing happens.

Can anyone characterize how their tow/haul button works.

On my '96 F250, when I was on the freeway and pressed the tow/haul button, it would always come out of overdrive and stay their. And when I was going down a hill and the truck was just coasting, I would press the button, and then I would have to give it a tiny bit of throttle, then it would downshift and hold a gear enough to slow the truck down.

My 2005 acts a little different in that I have to press the brake going down a hill for it to downshift and hold the lower gear. But on the freeway, when I press the button, nothing has ever happened.

Anyway, it doesn't work at all now. Just curious how others tow haul work.

Thanks.