I have a '99 Blazer w/ manual heater controls that does not have heat. The operating temp is normal at 195, coolant levels normal and flowing normal. I get no response when I adjust dial from off to any setting, defrost/heat, or otherwise. There is also no action from the blower when I turn the speed from off to 1,2, etc. I am hoping this is just vaccuum lines that failed after 10 yrs. I have not had a chance to look under the hood. Please help, it is -7 degrees out and getting colder. Thanks for the assistance.

Go over all fuses.
3 in end of dash and one underhood fuse block.
Blower motor controls is all electrical.

Def /vent/heat/dash air outlets are vacuum controlled.
Make sure you have good engine vacuum to controls.

On blower check for 12 volts to it and threw the resistor and at blower motor and also ground.