Ignition Switch: Testing and Inspection

Ignition Switch Testing:

***UPDATED BY TSB #T01192, JULY 10, 1992

The engine may not start without cycling the key to the "OFF" position and back to "START." A modified ignition switch with synthetic lubricant has been developed to remedy this situation. Vehicles experiencing this problem should have the modified switch installed. The mating harness connector must also be changed to a new material that is compatible with the synthetic lubricant in the new switch. For complete details, refer to TECHNICAL SERVICE BULLETINS.


ELECTRICAL TEST


1. Disconnect electrical harness by spreading apart locking fingers on each end of connector shell while pulling to separate from switch.
2. Test switch continuity using a self-powered test lamp or ohmmeter between blade terminals as indicated on image chart.
3. No continuity should exist between any switch blade connector and ground in any switch position except the two proof circuits (warning lamp check) in START position only.
4. Replace the switch if not as specified.

NOTE: For an "engine won't crank" condition with automatic transmission, determine if the condition exists in both "P" and "N" positions before checking ignition switch continuity. If the problem occurs in one shift position but not the other, a more likely cause is a defective transmission neutral start switch.

On vehicles with manual transmission, ensure that the clutch/starter interlock switch is operating properly.

MECHANICAL TEST

1. Rotate lock cylinder key through all switch positions.
2. Movement should not stick or bind and should return from START to RUN without assistance (spring return).
3. If sticking or binding is encountered, check for:
a. Damage to the lock cylinder key.
b. Insufficient lock cylinder lubrication.
c. Bent or damaged actuator rod.
d. Object rubbing against actuator rod.
e. Excessive rubbing of actuator against transmission shift socket (auto. trans.).
f. Binding lock cylinder or shroud rubbing against lock cylinder.
g. Burrs or foreign material around rack-and-pinion actuator in lock cylinder housing.
h. Binding ignition switch.

NOTE: DO NOT apply lubricant to inside of ignition switch.