When trying to put the Blazer into 4x4 Auto (push button) the yellow light blinks for about 1 minute and then returns to 2x (top upper right).

If I try to put the Blazer into 4x4 Hi (push button) the yellow 4x4 light blinks but never stops blinking.

When I turn on my Blazer the drive check indicates all is ok.

Any suggestions on what might be wrong?

Thanks for any ideas.

 

The transfer case and transmission are two separate items in the driveline of your vehicle. A problem with one does not necessarily equal a problem with the other.

If you have the auto4wd option, you have the NV236 transfer case. There are several things that can cause the transfer case to not shift properly from 2HI to the other 4wd modes. First, I would take a look at the connections to the switch in the dash, the TCCM located behind the passenger side kick panel, and the encoder motor located on the side of the transfer case. You are looking for corrosion. If corrosion is present, clean as necessary and make sure that the terminals in the connector can make a good connection to the pins in each component.

If the service 4wd light is on in the dash, the TCCM has stored codes which should be read since the TCCM is trying to tell you what it thinks is the problem. It requires a full feature scan tool though so it likely isn't going to be free.