Look in the left upper corner of your glovebox. I think there are 3 or 4 relays there. The one second from the left is the ignition relay. they do interchange and I believe they only cost about $8.00 each.
The high speed relay for the blower motor would be found under the hood, on the passenger side of the firewall, close to the blower motor speed resistor.
The Heater/Blower Relay is on the blower motor housing under the dash in the passenger compartment on 1999-2002 models
There is a fuse for the blower motor on the fuse panel, I do not know of a relay.
The blower motor relay for high speed would be located in the power distribution box under the hood.
Passenger side firewall near oil fill for the motor
it is next to the firewall near the heater coil
The only relay in the heater system would be for the high speed function of the blower motor. That rely would be located under the hood, on the firewall, close to the blower motor resistor.
The blower motor relay only operates the high speed function. That relay would be in the fuse/relay center under the hood. Once you have located the relay in the fuse/relay center, simply pull it straight out to replace it.
The fuse. The blower motor speed resistor. The blower motor relay. The blower motor switch. Check for power at the blower motor connection.
Only for the high speed blower function. The lower speeds go thru the blower motor speed resister.
Where is the location of fuel pump relay on 1996 Chevy Blazer?
mounted on the a/c unit near the fan for heater under the hood