K 3500 Truck 4WD V8-6.6L DSL Turbo VIN 1 (2001)
Glow Plug Relay: Description and Operation
The glow plug relay is a solid state device which operates the glow plugs on Federal Emissions Vehicles. The glow plug controller is a solid state device
which operates the glow plugs on California Emissions vehicles. Both components perform the same function of turning ON the glow plugs based on
ECM commands
The glow plug controller or relay is connected to the following circuits:
^
The fuel heater ignition 1 voltage circuit.
^
The battery voltage circuit.
^
The glow plug enable circuit (between the ECM and the glow plug relay or controller).
^
The engine ground circuit.
^
The glow plug supply voltage circuit (between the glow plug relay/controller and the glow plugs).
On the California Emissions vehicles, the glow plug diagnostic circuit connects directly from the ECM to the glow plug controller. On Federal emissions
vehicles, the Glow plug diagnostic circuit is spliced to the glow plug enable circuit after the relay.
