Aerostar AWD V6-183 3.0L (1991)
Fuel Pump Relay: Description and Operation
When the ignition switch is turned ON, the Electronic Engine Control (EEC) power relay is ENERGIZED, providing power to the fuel pump relay. Fuel
pump power is provided through the fuel pump relay contacts and an inertia switch. If the ignition switch is not turned to the START position in
approximately one second, a timer circuit in the Engine Control Assembly (ECA) will open the ground circuit to the fuel pump relay, causing the fuel
pump relay contacts to OPEN. This action stops the power supply to the fuel pump.
When the ignition switch is turned to the START position, the ECA closes the ground circuit to the fuel pump relay, resuming operation of the fuel
pump.
After the engine switch is returned to the ON position, power to the fuel pump is supplied through the fuel pump relay. The ECA monitors engine speed
and OPENS the fuel pump relay ground circuit if the engine speed drops below 120 rpm.
