Glow Plug: Testing and Inspection
Fig. 7 Glow plug system wiring diagram. 1984:
1984
Refer to wiring diagram, Fig. 7, then use the following procedures for troubleshooting and diagnosis of glow plug system. When troubleshooting system, the glow plug controller must be operated with engine below 122°F. If it is necessary to remove or test glow plug controller, ensure that battery ground cable is disconnected, since damage to electrical components may result.
No Wait Lamp-Engine Cold
1. With ignition switch in ``RUN'' position and engine off, check wait lamp operation. Wait lamp should be on. If not, proceed to next step.
2. Check gauge fuse. If fuse is blown, replace fuse and repeat step 1. If fuse is good, check pink and pink/black wires between ignition switch and S203 for opens.
3. Disconnect connector of glow plug controller. Connect a jumper wire at connector pin A (dark blue wire) to ground. If wait lamp does not go on, check for burned out bulb. If bulb is not burned out, check for opens in dark blue wire between controller connector and wait lamp, and also in pink/black wire between wait lamp and S203. If wires are not open, proceed to next step.
4. Connect one end of test lamp BT-7905 or equivalent to red wire terminal of glow plug relay and other end to ground, then touch lead to glow plug controller connector pin C (black wire). If wait lamp comes on, replace glow plug controller.
Wait Lamp Stays On More Than 15 Seconds
1. With ignition switch ``OFF,'' check battery voltage. Charge battery if voltage is below 10.5 volts.
2. Connect one end of test lamp BT-7905 or equivalent to ground, and the other lead to red wire post of glow plug relay. Turn ignition switch ``ON,'' then touch test lead to green wire post of relay. If test lamp comes on, the glow plug relay should operate. If relay operates, replace controller. If relay does not operate, proceed to next step.
3. Check diesel fuse. If fuse is good, separate connector at glow plug controller. Connect test light between pins B (pink/black wire) and C (black wire) at harness connector. Turn ignition switch to ``RUN'' and observe test lamp. If test lamp does not come on, check continuity of pink/black wires. If test lamp comes on proceed to next step.
4. Check continuity (less than 75 ohms) between pins B and C at controller. If no continuity is evident, remove glow plug controller, disconnect glow plug relay and replace thermal controller.
Engine Does Not Start---Wait Lamp OK
1. Ensure cranking speed is greater than 100 RPM. If not, check battery voltage and charge battery if necessary.
2. With ignition switch in ``RUN,'' use test lamp mentioned previously and check for voltage at pink wire of injection pump fuel solenoid. If no voltage is evident, repair wire. If voltage is present, proceed to next step.
3. Turn ignition switch ``OFF.'' Using a self-powered test lamp, check for continuity from fuel control solenoid to ground. If no continuity exists, replace solenoid.
4. Connect one end of test lamp BT-7905 or equivalent to ground, and the other end to red wire post of glow plug relay. With ignition switch ``ON,'' touch test lead to green wire post of relay. Test lamp should come on and relay should operate.
5. If relay operates, turn ignition switch ``OFF,'' then disconnect glow plug harness connectors at glow plugs. Connect self-powered test lamp between green wire post of relay and ground. At each glow plug, momentarily connect harness connector to glow plug spade terminal. Observe test lamp. If lamp comes on, glow plug and harness lead are OK. If test lamp does not come on, ground harness connector and observe test lamp. If test lamp comes on, replace glow plug. If test lamp does not come on, replace harness connector.
6. If glow plug relay does not operate, remove controller and relay. Check for continuity of both parts. Replace controller or relay as necessary.
1983
Refer to wiring diagram, Fig. 8 and Figs. 9 through 15, for troubleshooting and diagnosis procedures for the 1983 glow plug system.