Component Testing

S77 Transfer Case Shift Control Switch

1. Ignition OFF. Remove the S77 transfer case shift control switch. Refer to Transfer Case Selector Switch Replacement (Chevrolet / GMC)Transfer Case Selector Switch Replacement (Cadillac) .
NOTE:

Testing for Step 2 is performed on the component using the L-BU probe J 35616-65B.

2. Measure the resistance for each of the range positions of the S77 transfer case shift control switch between the 5-volt reference circuit, terminal 11, and the switch signal circuit terminal 12.
   • If the resistance is outside the specified ranges 

     Replace the S77 transfer case shift control switch. Refer to Transfer Case Selector Switch Replacement (Chevrolet / GMC)Transfer Case Selector Switch Replacement (Cadillac) .

   • If the resistance is within the specified ranges 
3. S77 transfer case shift control switch OK.