F 250 2WD Pickup V8-7.3L DSL Turbo VIN F (1994)
Glow Plug Relay: Description and Operation
PURPOSE
The Glow Plug Relay (GPR) supplies power to the glow plugs for cylinder warming to improve cold-engine starting.
OPERATION
The Powertrain Control Module (PCM) uses the Engine Oil Temperature (EOT) sensor and Barometric Pressure (BARO) sensor to determine
how long the glow plugs will be on. The PCM then controls the GPR with the Glow Plug Control (GPC) signal. When the GPC signal is grounded
by the PCM the GPR closes, turning the glow plugs on.
CONSTRUCTION
The glow plug relay is one piece, and is serviced as an assembly.
NOTES
The PCM energizes the glow plugs longer if the engine is very cold or if the barometric pressure is low at high altitudes.
