The fusebox which controls the blower motor is under the hood up by the firewall.
Swap the relay with a known good one, many of the relays are of the same part number. Keep in mind that the blower motor relay only controls the high speed function. The blower motor speed resistor and the blower motor switch controls the lower speeds.
First, take a socket wrench to remove the cover of the blower motor of a 1993 Chevy truck. Then pull the motor blower out and install a new one in its place. Lastly, screw the bolts of the blower motor cover back in.
In the truck!
Your truck has both. the resistor is between the switch & blower.thje resistor controls the blower speed
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.
You will have to replace it. The bearings are worn out in the blower motor.
The blower motor can be replaced on a 1995 Chevy truck by first disconnecting the battery. It helps to take a picture of the blower motor before dismantling, so that it can be put back easily. Disconnect all the wires from the motor, then remove the bolts holding it to the firewall. Replace with the new motor and bolt it in, then connect the wires. Reconnect the battery.
You gotta start by figuring out what's wrong with it. You need to determine if it's the blower motor itself, or the power supply, then troubleshoot to determine the exact cause.
behind the glove compartment, to the left
There could be two separate problems. Check the blower motor resister, and the ABS sensors for problems that could cause this.
1999 S10, it should be under the hood, on the firewall, on the passengers side, close to the blower motor.
The blower motor resistor pack is defective. Replace it.