Test B: The Front Axle Does Not

Pinpoint Test B: The Front Axle Does Not

Test B1:

Test B1-B3:

Test B3-B5:

Test B6:

CAUTION: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

Engage Correctly
Normal Operation
With the key in the ON position, the 4WD control module (PCM) supplies power and ground to the transfer case clutch through circuit 779 (BR) and 976 (OG). If the transfer case clutch circuit is not active, the vehicle will not operate in AWD. Check circuit 779 (BR) for an open or short to ground. Check circuit 976 (OG) for an open. If both circuits prove out, check the transfer case clutch for an open in the clutch coil. If the transfer case clutch is operating correctly, the fault would be in the 4WD control module (PCM).

Possible Causes
^ Circuit 779 (BR)
^ Circuit 976 (OG)
^ Transfer case clutch
^ 4WD control module (PCM)