How do i test 1998 buick lesabre blower motor with a hot wire

SOURCE: blower motor won't run on 2005 buick lesabre

There are two fuses on that circuit I believe. There is one labeled HVAC CTRL and HVAC HI, both should be located in the fuse block inside the car. Check both of those and make sure they are good.

As well, there is also a blower motor resistor that is located in the blower motor housing. Its very common for these to go bad and can cause issues with the motor not operating as well.

SOURCE: Can't find the blower motor resistor on a 1998

I dont believe that is a resistor controlled circuit. I think it is a transistor controlled circuit mounted on the firewall cdcneter area.
you can have slow air inside but no high speed air if the module is defective.

SOURCE: Blower motor resistor

I believe it's behind the glove box. Once you remove the glove box it's easy to get to. Hope this helps.

SOURCE: 2000 BUICK LESABRE BLOWER MOTOR

The blower motor should be two wires. Backprobe and find out which is power and which is ground and bench test it. You could have a bad blower but it sounds more like a defective speed resister.

SOURCE: '91 Buick LeSabre heater blower motor

Are you sure the blower motor is defective? If the blower motor resistor pack is bad the blower will not work. Have you applied 12 volts directly to the blower motor to verify it is bad? I have not replaced a blower motor on your particular car but it is usually a labor intensive repair. Depending on where you have it repaired the cost could be as little as $150 and up. Hard to say without actually doing it. Replacing the Resistor Pack is a fairly easy repair, so hopefully that is your problem.