has no reverse, no codes, I don't have manual, thinking its the directional control box, pwr steer mtr comes on when fwd selected, doesn't when reverse is selected, the back up alarm does come on, the truck has north of 31,000 hrs. on it, aftermarket price on the box is $1100.00 , so I don't want to order without a schematic, just wondering if anyone had this issue before.