00 Blazer, Service 4x4 light on and 4x4 not working

Well lets try to take the long story in a case like this. You never know what could be important. About 3 mths ago my service 4x4 light would come on, but 4x4 worked fine. So being the imgnorant person I am I ignored it. Now I am paying for that mistake. The Service 4x4 light will come on about 5 min after turning the key on. Does not matter if the engine is started or not. So basicly if I turn the key on to the "Acc" positon the service light comes on too. When I push one of the four buttons to change it to anything else nothing happens. No blinking, no tinking, no sounds.

Anyone got any ideas for me?

p.s already searched the forums.....

you need to get the code(s) first from this system to be able to narrow it down to what it is, and go from there.

B2527 is the code. I have tried replacing the 4 button control unit with no avail. Any ideas?

Well I guess they are telling me that my transfer case shift control module is out.... nice little 700 dollar bill there... Anyone know where to buy aftermarket instead of gm?

Ebay