Looking were isblower resistor - 1999 Oldsmobile Alero

Change the resistor. For the 15-20 bucks it's a great diagnostic and a very common problem with GM vehicles.
Then you can start backtracing the harness as ray012965 suggested.

What code did autozone say you had. Ballast resistors have been used in cars since the late 1970's.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Before removing the heater switch on this 2006 citroen hdi I would first have the blower motor checked and the most common reason for this and other blower problems would be the blower resistor.

Your blower works on and off at times, first locate the blower motor and the resistor. the blower motor is located on the heater box, look under the pass/side of the dash, you may have to remove under dash cover to see blower.
When you have located the blower now look to the side on the heater box, there you will see a connector plug, it plugs into a connection on the heater box, this will be the resistor, the resistor slides into heater box and the end of it bolts to box to hold it in place and then the connector plugs into it, if you can not locate it then follow wires that plug into blower , follow wires back they will lead you to resistor,
next time blower does not work wiggle connector to resistor and see if blower turns on, if it does then resistor is the problem. also unplug resistor plug at resistor and check for any burning of connectors at plug and inside resistor.

I would bet its a bad resistor or the plug is brunt due to high draw from bad connections, if plug has burn damage to connectors then replace the plug along with resistor.

Iwould look blower motor resistor, that is the most common problem, if the fuses are good it must be the motor or the resistor and i would say the resistor, the resistor is what controls the speed of the blower, this is located on the heaterbox, if you follow the wires that plug into the blowermotor it will lead you to the resistor. good day.

under the dash,behind the glove box,

If it is the manual system ( sounds like it is ), I would suggest taking a look at the blower motor resistor.

To gain access to it, look under the glove box, you will see the bottom of the blower motor. Attached to it is the blower motor resistor.

This is what you are looking for ( towards the left side of the picture ) :


Could be the blower motor resistor, or the resistor and the pigtail that is the problem

Your looking for the blower resistor. Its on the passenger side under the dash. Two of the wires go the the blower motor. The wire connector and the resistor can burn or corrode. The replacement is easy two screws hold the resistor in and the connector can be replace with **** connectors.

on level ground with the engine at idle pull out the dipstick wipe it off and check that the fluid is between the two marks.  Keep the level near the top mark but do not overfill.

It is the blower motor resistor. Look under the passanger side dash and locate the fan housing (looks round and black in color. Then locate the resistor it will be in that housing usually withtwo ten millimeter nuts or two simple screws holding it in. unplug the harness to the resistor and remove the resistor. Part store price is approx. 50.00. Note: on aftermarket (not Jeep) resistor sometimes you have to modify the housing a little to get it in. Hope this helps.

Hi..The Blower Motor Resistor is located under the glove compartment, pass side. You do not need to remove the glove box, or anything. Look under the dash on the pass side and you will see the resistor with the wires leading to it. (looks about the width of a Credit card) Simply undo the ( 2 ) 9 or 10mm screws from the resistor, slide/pull it down from the slot, un-clip the wire harness and replace with the new resistor. Screw it back up. Thats it. Takes about 4 minutes. The dealer wants $125.+ to do the job. The resistor is about $24.00.
Good Luck. If it keeps blowing, the blower motor is probably drawing too many amps. Then you have to switch that out.
Mike