I can here the tranfercase locking in but its not turning front tires at all ?
Your vehicle had option of two different 4x4 systems ,
New Venture Gear 263 Selectable Two Speed Transfer Case
The NVG 263 transfer case features a three button shift control switch located on the instrument panel. When the vehicle has the ignition key in the RUN position, the transfer case shift control module starts monitoring the transfer case shift control switch to determine if the driver desires a new mode/gear position. At a single press of the transfer case shift control switch, the lamp of the new desired position will begin flashing to inform the driver that the transfer case shift control module has received the request for a new mode/gear position. The lamp will continue to flash until all shifting criteria has been met and the new mode/gear position has been reached (or has been engaged). Once the new mode/gear position is fully active, the switch indicator lamp for the new position will remain ON constantly.
The NVG 263 transfer case provides the driver with 3 manual mode/gear positions:
• 2HI - 2 Wheel Drive high range
• 4HI - 4 Wheel Drive high range
• 4LO - 4 Wheel Drive low range
OR
The NVG 236/246 transfer case features a 4 button shift control switch located on the instrument panel. When the vehicle has the ignition key in the RUN position, the transfer case shift control module starts monitoring the transfer case shift control switch to determine if the driver desires a new mode/gear position. At a single press of the transfer case shift control switch, the lamp of the new desired position will begin flashing to inform the driver that the transfer case shift control module has received the request for a new mode/gear position. The lamp will continue to flash until all shifting criteria has been met and the new mode/gear position has been reached, or has been engaged. Once the new mode/gear position is fully active, the switch indicator lamp for the new position will remain ON constantly.
If there are problems with electronic part of the systems the shift control switch light will flash warning of a problem , If no lights you have a mechanical problem in the transfer case itself .
The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator motor consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly.
The front axle actuator has four circuits connected to it, a front axle feed circuit, front axle ground circuit, front axle control circuit and a front axle switch circuit.
Whenever a shift to AUTO 4WD, 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.
Tests for proper power and ground at the front axle actuator.
Tests the operation of the front axle control circuit.
Helps determine if the transfer case shift control module is able to monitor the front axle switch.
Tests the front axle switch circuit for an open or high resistance.
Measures the voltage between the front axle feed circuit and ground.
Tests the front axle control circuit for an open or high resistance.
Inspects the front axle for a mechanical malfunction.
Tests for open in the front axle feed circuit.
2/14/2016 8:55:19 PM •
2001 GMC Yukon
•
Answered
on Feb 14, 2016
•
527 views