There could be several reasons, but the most common when the fan works on high, but none of the other speeds is that there has been a failure in the fan speed control RESISTOR PACK. At the high speed setting, the 12 volt vehicle supply is fed directly to the fan motor. On all the other speed settings the voltage is proportionally reduced by the series combining of heavy wire resistors. The resistor package is inserted into a rectangular opening in the blower plenum chamber [encloses the heater core, and the air conditoner evaporator coil]. Depending on the vehicle, it may be on the passenger or the engine compartment side of the firewall/cowl. It is normally secured in place with two to four screws, and the wiring harness is connected to the pack with a plug on connector. j3h.
there is a resistor that controls the speed and should be near the blower motor its called blower motor resistor
i have a 1998 buick century and my blower motor is under the passenger side front wall inside.I found out that the blower motor resister was the problem.if it works on high speed only,replace the resistor first.it's cheaper but harder to get at.
Check the blower resister
the blower switch itself is located in the instrument panel. it adjust the speed of the blower. the blower resistor, if that is what you are looking for,is located beside the blower motor under the pass. side of the dash
If you are referring to the blower motor only working on the high speed setting, then the problem is the blower motor Resistor Pack is defective. Replace it. It can be the blower motor speed control switch but not likely.
my 1999 winstar was doing this and it was the blend door
either your blower is bad, or you need a a/c recharge.
under dash on pasenger side
Either than switch, the resistor, or the relay is bad. On my 1999 Buick Century, the blower motor quit working on the three lower speeds, and then went out completely. When the resistor goes bad, the lower speeds quit working. My blower motor was squealing, also. After I replaced the blower motor and the resistor, I tested it and found the blower worked great on every speed but high. It turned out that there is a separate circuit for high speed, and the fuse was blown. I replaced the fuse for the high speed, and the blower now works on all 5 speeds. Replacing the blower and resistor was difficult, but not as bad as expected, thanks to help from this site.
The blower motor relay for high speed would be located in the power distribution box under the hood.
Sounds like it could be the actaul switch that's used to select the speeds. ADDITIONNAL INFO SEE DISCUSSION PAGE.
If you are saying the blower motor only works on the high speed setting, then the problem is a bad HVAC Resistor Pack.
Speed sensors are allways installed on the transmission. Find the wire plug 99% that's it !
change the blower motor resistor . this controls the speeds . thanks paul
If you mean the fan works on high only it's the blower motor resistor.
do you know how to shift correctly? no offense and some vehicles do that.
If the blower motor only works on high speed, which in your case is speed 5, it is a definite that the blower motor resistor needs to be replaced. When choosing all the other speeds the current travels through a certain resistor, which in turn slows down the speed of the blower motor. High speed is direct 12 volts to the blower motor. So when it works only on high speed there is a 99.9% chance that the blower motor resistor is shorted or blown and needs to be replaced I have a 99 grand am as well and I have heat but it only works on setting 5. I replaced the resistor last night and it was horrible(broken, melted, discolored) Put the new one in and still no heat on any setting but 5. I am going to replace the climate control panel to see if that is the issue in my car. If you have no heat you may want to consider adding antifreeze. Sometimes the grand am's have bad coolant sensors.
the blower resistor is bypassed on high. a direct path to ground. if high is the only operational speed the resistor is bad.
Defective Blower Motor Resistor Pack.
Have you checked your coolant? Kind of obvious but sometimes overlooked.
Wikianswers cannot provide pictures or diagrams.
If you have checked the blower motor and it does function when power is applied then I would suspect the Blower Motor Resistor Pack is defective. It is also possible the blower motor speed control is bad, but highly unlikely.
Blower motor: remove the glove box and you will see the blower motor and blower resistor.
If the blower works on high speed, but not on any of the lower speeds, that usually means that the blower motor speed controller is bad. There is a resistor in there which can overheat and burn out. If the blower motor has a bad bearing (makes noise or doesn't turn as fast as it should) that would cause the system to draw more current than normal, and burn out the resistor. If that is the case, you can replace the speed controller, and that would probably fix the problem, but likely it would return in a relativly short time. Without vehicle info, a step by step instruction would be rough... But that is a place to start in you search. Hope this helps.
Not sure about a 1999 but on a 2000 the blower relay is on circuit C-108 in the Junction Box.