[wirenut699]

I see you have another post for the HVAC blower motor

You may have a fuse or fuses out or a break in the power wiring.
Are these the only things out? Check the fuses. Double check that nothing else is out, such as cruise control, ABS, 4WD buttons. This will give clues as to where the problem is.

The 1999 blazer has fuses in 2 locations: under the hood above the left fender in a black plastic box and on the left side of the dash at the driver's door hinge area.

At the dash fuse block Fuse 9-HVAC is for blower control circuit if you have manual AC, or Fuse-21 if you have climate control.
Fuses-4, 11, 19 are for various parts of the instrument panel. Are the other gauges working?

Under the hood there is a 30amp fuse marked HVAC which is for blower power circuit.

Post back after you check the fuses.