Gauges
 

Chevy 1999 blazer LS 6 CYLINDER, 2 WHEEL DRIVE, my gas gauge display,
my temperature gauge display and my auto transmission gear display (on the dashboard P, R, N,D 2,3) STOP WORKING @ THE SAME TIME. CHECKED ALL THE FUSES AND THE RELAYS ALL OK. Could someone tell me what to do next?
I need to fix this problem ASAP, HELP NEEDED.

new gauge cluster assembly.... go to a dealership or find one online replace the whole assembly, much easier than pinpointing the problem

I know you said fuses checked, but recheck the 15 AMP fuse for the 4WD I believe it is fuse 5. This controls the fuel guage, the low fuel light will be on, the gear indicator highlight will be off and the Battery icon above fuel guage will be on.