My 4wd switch just flashes ...will not engage 4wd. Could it just be the cold. on 2001 Chevrolet Tahoe

works in 2wd fine...if I press auto or 4 wheel hi the light just flashes

Asked by for the 2001 Chevrolet Tahoe
2 answers
scan codes and post so we can adv
System stores codes so diagnosis is not very tough....Encoder motor failures are not uncommom.