Tonight I went out for cofee and when I started the truck which is a 2006 silvy 4x4 crew cab with factory tow package, the tow haul light was on and would not go off by pressing the button. the truck was reving like it should when tow haul is engaged. I went inside for a cofee. When I started the truck again everything was normal. what would be causing this? Is there something getting ready to fail and is there anything that I can check?