i have 1999 chevy 4x4 z71.The 4wd wont engage in hi or lo lights just flash. on 1999 Chevrolet Silverado 1500

when i push the button light just flash dont know if it is the swicth or what

Asked by for the 1999 Chevrolet Silverado 1500
2 answers
could be the switch or the shift solenoid
most likely the switch,scan codes and post so we can adv