Service Soon Light Inoperative

1984

1. Turn ignition on and observe coolant temperature light. If light is not lit, proceed to step 2. If light is lit, proceed as follows:
a. If ``Service Soon'' light is not lit during engine cranking, check condition of lamp bulb and replace as necessary. If bulb is satisfactory, check circuit 499 for an open.
b. If circuit is satisfactory, fault is in ECM or ECM connector. Repair or replace as necessary.
2. If coolant temperature light is not lit, proceed as follows:
a. Check condition of 20 amp GAGE fuse. If fuse is blown, replace fuse and repair short to ground in circuit 39. If fuse is not blown, proceed to step 2b.
b. Measure voltage at fuse with ignition on. If voltmeter reads 12 volts, repair open in circuit 39. If no voltage is recorded, repair open in fuse feed circuit.