4 wheel drive not working

If the 4x4 light on your 2001 Chevy Blazer is blinking when you try to engage 4 Hi or 4 Lo, it indicates a problem with the 4WD system. When the light blinks instead of going solid, it typically means that the transfer case has not fully engaged into the selected 4WD mode.

Here are some possible reasons for this issue:

Transfer Case Motor: The transfer case uses an electric motor to engage and disengage the different 4WD modes. If the motor is faulty or not working correctly, it may not be able to complete the shift into 4 Hi or 4 Lo, resulting in the blinking light.

**Transfer Case Actuator: ** The transfer case may have a shift actuator that physically moves the transfer case into the desired mode. If the actuator is malfunctioning or sticking, it can prevent the transfer case from fully engaging, causing the light to blink.

Faulty Sensors or Switches: There are various sensors and switches involved in the 4WD system, such as the 4WD position sensor, transfer case position sensor, or mode selector switch. If any of these sensors are faulty or sending incorrect signals, it can lead to problems with engaging the 4WD system properly.

Electrical Issues: Check for any loose or damaged wiring related to the 4WD system. Even if the wires on the passenger side panel look fine, there could be a wiring issue elsewhere that is affecting the 4WD engagement.

Transfer Case Fluid Level and Condition: Ensure that the transfer case has the correct fluid level and that the fluid is in good condition. Low or contaminated fluid can cause issues with the transfer case operation.

Troubleshooting and diagnosing the 4WD system in your Blazer may require a scan tool capable of reading the 4WD system codes and performing diagnostic tests.