F 250 2WD Pickup V8-7.3L DSL (1990)
Fuel Tank Selector Valve Schematic
FUEL SELECTOR VALVE - VEHICLES W/DUAL TANKS ONLY
The 6-port diesel fuel valve is powered by a small electric motor which opens and closes the valve ports. The supply and return ports for either tank open
and close simultaneously. The valve is shifted to the front mode (that is the front supply and return ports open to the engine supply and engine return port
respectively) by applying a positive 12 volts to terminal number 1. When the valve reaches the front mode position, an internal switch opens the circuit
and stops the motor. Returning the valve to the rear mode is accomplished by reversing power: positive 12 volts to terminal number 1 and ground to
terminal number 2. Terminals 3 to terminal 4, this supplies the front tank sender signal to the fuel gauge. Terminals 4 and 5 are connected to the in the
rear tank mode. Therefore, a change in the fuel reading gauge (assuming at least 1/4 tank fuel level difference), means that the valve has shifted.
