Diesel Engine - Glow Plug System Operation
Number 84-6 (Diesel)-10 Date 4/84Subject: DIESEL ENGINE GLOW PLUG SYSTEM OPERATION 4.3L V-6 AND 5.7L V-8 - 1984 MODELS
Information provided in the 1984 Service Manual indicates that the thermal control in the glow plug controller allows current to flow continuously to the relay, thus preventing the glow plugs from cycling. This is incorrect, the 1984 system may cycle. Voltage to the controller that exceeds 13 volts will cause the controller to shut off current to the glow plugs. The current will stay off for a few seconds and then come back on. If the current still exceeds 13 volts it will continue to cycle on and off. A voltage that exceeds 13 volts will normally only occur when the alternator is charging. The glow plugs will then cycle on and off for a short period of time. This is considered a normal condition.