2006 Porsche cayenne, blower motor. I replaced blower motor 2 years ago. 3 days ago blower fan stopped working. replaced the regulator. Everything works fine. Two days later,it is not working again.

SOURCE: Blower motor or resistor?

If it was the motor that went out then it would not blow at all. The resistor is the culprit that starts killing off speeds. It should be about $25 to $30 at an aftermarket store like autozone or advanced auto parts.

SOURCE: 2006 Ford Explorer XLT the Blower Fan only works on 4 and 3 Sp

Look under the dash on passenger side and just to the left of the blower motor housing you will see the 4WD control module.Remove the 2 screws holding the module and let it hang down and your resistors are behind this.Remove the 2 screws holding the resistors and remove.
Now I am assuming you have manual climate control and not electonic.

SOURCE: Blower motor or resistor?

Yes its the blower motor resistor.

More then likley theres some trash or something in it, or possibly the motor itself is on it's way out. There not that bad to pull out of that body car, just pull it out and see what you can see.

The blower motor is under the glove compartment

You can replace the resistor on your own. Please find a detailed diagram which would guide you to do it.

http://autorepair.about.com/library/images/bl629a-lib.htm

Thanks

SOURCE: location of blower motor fuse

Fuse blower motor is not in the fuse box. It is located outside. lOpen the hood, on the driver side near the fender, about 1 feet from the fuse box toward the direction of the radiator, there is a retangular about 1x2 in with wire coming out from each end. Snap it open, inside is the the wire fuse.

SOURCE: BLOWER FAN NOT WORKING PROPERLY

I had the same problem change your blower motor resistor.