Wait Lamp Stays on Longer Than 10 Seconds

Fig. 2 Glow plug wiring schematic (Part 1 of 2). 1982-83 models:

Fig. 2 Glow plug wiring schematic (Part 2 of 2). 1982-83 models:

1. Check glow plug relay operation. Disconnect connector at diesel diode module, Fig. 2. Connect one end of test lamp to ground and other end of test lamp to red (front) post of glow plug relay. Then touch test lamp to rear post (dark blue and black wires) of glow plug relay. Test lamp should light, indicating glow plug relay is operating properly.
2. If test lamp remains OFF, proceed as follows:
a. Check ECM fuse and ground connection G104.
b. Disconnect connector from thermal controller. Connect a suitable test lamp between pin 3 (pink/black wire) and pin 6 (yellow wire) of harness connector. If test lamp lights with ignition ON, check continuity between pins 3 and 6 of thermal controller. If test lamp remains ON, replace thermal controller.
c. If test lamp remains OFF, connect a suitable ohmmeter to glow plug relay coil, and check resistance of coil. If ohmmeter indicates a high glow plug relay coil resistance, replace coil. Check continuity of pink/black, yellow and black wires.
3. If test lamp lights (glow plug relay is operating properly), proceed as follows:
a. Disconnect ``Wait'' lamp control relay connector. ``Wait'' lamp should go OFF. Connect test lamp between white and yellow wires of connector. If test lamp lights, replace ``Wait'' lamp control relay.
b. If test lamp remains OFF, turn ignition OFF. Connect a suitable ohmmeter to pins 4 and 5 of thermal controller, and check for 30 ohms resistance. If ohmmeter indicates more than 30 ohms, replace thermal controller. Check continuity of black, dark green, dark blue, orange or orange/black, white, yellow and black wires.