B350 1 Ton Van V8-360 5.9L VIN W 4-bbl (1988)
Spark Control Relay: Description and Operation
The Dual Pick-Up Start Run Relay controls which of two pick-up coils is used in a dual coil distributor. When the ignition is in the START position the
relay is energized, connecting the start pick-up coil to the Electronic Control Unit (ECU). This allows a fixed amount of advance timing for easy starting.
When the ignition switch is in the RUN position the relay is not energized and the run pick-up coil is connected to the ECU. The Dual Pick-Up Start Run
Relay is only on vehicles equipped with a dual pickup distributor.