[Alexxn 00 Si]

Hello all, My 200 Blazer won't go into 4 WD now for some reason....the other day a dash light came on that said "Service 4WD" and since then if I press either the Auto 4WD or the 4Hi buttons they just blink on and off and it never goes in. Does anyone have any idea if this is a common problem with an easy fix ? We're getting snow this weekend and my dealer appointment isn't until Monday so I'd like to fix it myself.

Thanks !