sounds like you need to check all the light switch, ignition switch and fuse panel [if there is one] connections, there should be no interaction between the light switch and the turn switch .... the turn switch always has power available because the brake lights transit there, but the brake power comes from a terminal on the light switch [the T terminal is tail lites controlled by that switch, the stop sw gets power from the always hot BATT terminal] .... you might check the
mess of connectors under the cab to insure the right color wires match up, and check the big connector at the column for mixed color positions too
have you done a complete re-wire on this truck? or maybe a PO did? I'd get out the wiring diagram and start checking .... could still be a misplaced ground somewhere too
Bill
