Wait To Start Light: Description and Operation

Glow Plug Indicator






The Glow Plug Indicator (GPL) is located in the instrument cluster and is used to prompt the operator when the engine is ready to be cranked and started. When the light goes out, the vehicle is ready to start. As a bulb check, the light is commanded on at every key cycle even though the glow plug system may not be required. On-time normally varies between 1 and 10 seconds. Wait to Start indication is independent of glow plug relay on-time as the glow plug system can stay on after the indicator goes off.

F-250/550 and Excursion

The indicator is controlled by the instrument cluster, based on electronic information from the PCM. The PCM sends an electronic signal command, via Standard Corporate Protocol (SCP) communications, to the cluster on how long to keep the indicator on. The instrument cluster performs diagnostics for the GPL circuit.

F-650/750 and E-Series

The indicator lamp is turned on by the PCM. The PCM performs diagnostics for the GPL circuit.