Component Tests and General Diagnostics

1. Place the ignition switch in the RUN position (engine OFF) with 4WD engaged. It may be necessary to rotate the front tires slightly for the front axle to fully engage.

2. Disconnect the electronic synchronizer connector at the transfer case. Connect a test lamp from the wiring harness connector to a ground. The test lamp should light.

3. If the test lamp does not light, check the circuit for opens. If none are found, replace the relay.

4. If the test lamp light in step 2, check the synchronizer coil for continuity. If the coil is open, replace it. If the synchronizer has continuity, it is probably OK. Recheck fluid levels, linkage adjustment, etc. before presuming the synchronizer to be faulty.