Q: Turn knob to four wheel drive but won't go into four wheel drive. I changed the switch and actuator but it won't work

Hello. The 4WD system consists of a module, encoder motor, and actuator. The module operates the transfer case (component that sends power to the front differential). The transfer has an encoder motor that shifts the transfer case by the commands of the module. The front differential has an actuator to engages the axle assemblies to the differential. The flashing light is a default operation of the module. The module’s data would have to be read and look for any fault codes in the system. If you’d like to have this looked at, a certified technician from YourMechanic can come to your location to inspect this issue in person and advise you on repairs.