Glow Plug Controller

A faulty controller/relay assembly may result in excessive white smoke in exhaust and/or poor idle immediately after starting. The following procedure checks for proper operation of controller circuit.

1. Turn ignition to "RUN" and allow glow plugs to cycle. Wait 2 minutes, then turn ignition to "CRANK" for 1 second and back to "RUN". Glow plugs should cycle on at least once. If glow plugs do not cycle as described, proceed to step 2.
2. Disconnect controller connector. Connect 12-volt test light between harness connector terminal "B" (Purple wire) and ground. With ignition in "RUN" position, test light should be off. With ignition in "CRANK" position, light should be on.
3. If test light does not operate as described, repair short or open in engine harness Purple wire. If light operates properly but glow plugs did not cycle in step 1, replace controller.