Glow Plug Testing

*** UPDATED BY TSB #288609 NOV 1986

1. Disconnect the wire from the engine coolant temperature sensor.
2. Connect a test lamp to a good ground on the engine, connect the other end of the test lamp to an accessible glow plug, and turn the ignition key to the run position for about fifteen seconds. If the test lamp does not illuminate perform the tests outlined under "POWER SUPPLY" in this section.
3. If the lamp illuminates, disconnect the power lead to the glow plugs and the common lead between the glow plugs. Connect one end of a test lamp to the positive battery terminal, and check each of the glow plugs for continuity by probing the terminal with the test lamp. Replace any glow plugs that do not show continuity by illuminating the test lamp.
4. If the glow plugs are receiving voltage and the glow plugs test good, but cold starting is still difficult, remove the glow plugs and inspect. If the glow plug is worn, replace the glow plug and check the injectors for proper spray pattern.
If any glow plugs are replaced, torque the new glow plugs to 22 ft. lbs. (30 Nm). This torque must not be exceeded because increasing the torque beyond the specification will cause closing of the ring gap, which can lead to premature failure of the glow plug.