The blower motor relay for high speed would be located in the power distribution box under the hood.
In most cases, you will find the speed shift sensor for your 1998 Chevy Blazer located on the backside of your transfer case. The transfer case is located on the transmission.
Should be behind the glove box. The blower motor speed resistor is located under the hood, on the firewall, passenger side, close to the blower motor.
Where is the speed sensor located on a 2005 Chevy Trail Blazer 6 cyl
The blower motor high speed relay is located under the hood, on the passenger side firewall close to the blower motor. The blower motor speed resistor is also located in that same area.
You didn't mention what year S10 Blazer you have but, the blower motor speed resistor can be found under the hood, on the passenger side of the firewall, close to the blower motor.
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 VSS is located in the top left hand side of the transfer case.
The speed sensor is located on the transmission on tail shaft behind the transfer case
The fuse. The blower motor speed resistor. The blower motor relay. The blower motor switch. Check for power at the blower motor connection.
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.
It depends on if its 4x4 or 2x4. On the 2x4 version its located on the rear of the transmission. If its 4x4 it is located on the transfer case.