i own a 97 f150 lariat 4x4 and ive been having some elc problems, when driving the 4x4 low range light comes on and the truck boggs down. its random, but then the light goes off and the truck goes back to normal. and then just today the heater started staying on when i shut the truck off but if you turn it to the off position and then back it wont work. any help would be be great