Fuel Pump Control Unit: Description and Operation

Transfer Pump Control Unit:

The fuel transfer pump control unit, located under the drivers seat, controls power to the transfer pump.

The control unit incorporates a timer and a relay. The timer delays the operation of the pump for ten seconds after the ignition is turned "ON".

A float switch in the fuel tank (part of the fuel gauge assembly) signals the fuel level to the transfer pump control unit. When the tank is just about empty, the float switch closes, grounding a terminal of the control unit. The control unit then interrupts the power to the transfer pump, turning the pump "OFF".