Glow Plug System Diagnosis
If glow plug system does not operate correctly and all connections are intact and inhibit switch is operating, perform the following diagnostic tests:
- Connect an ammeter in series between glow plug controller and left bank of glow plugs (glow plug controller is located on top, rear of valve cover). See Figure.
- "G" Series Van - Orange wire at controller is for left bank glow plugs. Red wire at controller is for right bank glow plugs.
- "C/K" Models - A pair of Grey wires are attached to glow plug controller. Color changes to Orange going to left bank glow plugs and Orange/Black going to right bank glow plugs.
- "R/V" & "P" Models - Information for "R/V" & "P" not available at time of publication. Use Fig. Figure as a reference and trace wire from controller to left bank glow plugs.
- Move ignition switch to the "RUN" position. Engine and accessories must be off and the glow plug system operating. Ammeter reading must be at least 55 amps. If ammeter reading is within specification, glow plug system is operating correctly. If ammeter reading is not within specification, one or more glow plugs is inoperative.
- Check individual glow plug leads by connecting ammeter in series with each wire attached to a glow plug. Each glow plug wire should read about 14 amps.
- If ammeter readings are as specified, glow plugs and wiring are okay. If reading is less than specified, check for continuity by disconnecting glow plug lead and connecting a 12-volt test light from connector to ground. Operate glow plug system.
- If test light glows, wiring is okay. Replace glow plug(s). If test light does not glow, repair or replace harness. Retest glow plug(s) for proper operation. Repeat above procedures for right bank of glow plugs.