My owners manuel list the blower relay as being in slot 12 in the fuse box under the hood on the drivers side.
Could be hi-speed fan relay or secondary winding in blower motor
Not sure about a 1999 but on a 2000 the blower relay is on circuit C-108 in the Junction Box.
Attached to the blower motor under the passenger dash
Dealer.
Check the fuses first and the blower relay.
The starter relay on a 1999 GMC Suburban with the bib block engine is located on the solenoid for the starter. The solenoid for the starter is on top of the starter.
The Heater/Blower Relay is on the blower motor housing under the dash in the passenger compartment on 1999-2002 models
The blower motor relay for high speed would be located in the power distribution box under the hood.
under the glove compartment
thats because your blower went out
looking for help on the brake light ground wire location for 1999 gmc suburban 4x4
The blower resistor on a 1999 Chevy truck Z1500 is located behind the glove compartment. There is also a resistor on the firewall next to the blower motor itself.