I have an 01 suburban 1500 4x4. The 4 wheel drive is push button. It's not working. I push the 4 hi or 4 low or auto and the lights switch to whatever button I push. Also, I can hear the actuator working. I have no idea what it could be. I heard if your abs light is on it won't engage so I got that problem out of the way and it's still not working. Any ideas? Thanks.