See Figures 1, 2, 3, 4, 5, 6 and 7
The auto glow system provides the pre-glow (fast glow) operation before the engine starts, as well as after-glow operation after the engine has started. The system consists of a water temperature sensor, glow plug relays, dropping resistor and glow control unit.
The system incorporates a glow plug light on the instrument cluster. The length of time that the light is on is controlled by the temperature of the engine.Pre-glow
The pre-glow system operates for about 6 seconds when the engine temperature is below 122°F (50°C). After the engine starts, the pre-glow system turns OFF.After-glow
The after-glow system operates for a specified length of time after the ignition switch is turned from OFF or ST to ON , when the engine temperature is below 122°F (50°C). The length of time varies from 5 to 32 seconds. After pre-glow, the after-glow system turns OFF when the terminal voltage of the glow plug is higher than 7 volts. When the ignition switch is in the ST position, the after-glow system is energized.
Glow Control Unit Terminals
See Figure 8
Water Temperature Sensor
- Remove the sensor from the engine and place in a pan of water.
- Measure the resistance with an ohmmeter at varying temperatures.
Compare the readings to the following values:
- Replace the sensor if found defective.
Remove the glow plug from the engine. Using an ohmmeter, check that there is continuity in the plug. If not, replace the glow plug and torque to 25 ft. lbs. (34 Nm).Dropping Resistor
See Figure 9
Disconnect the resistor and measure the resistance between the 2 terminals. The resistance should be about 0.1-. If not, replace the dropping resistor.