Kitchenaid classic mixer stir speed doesn't work.

SOURCE: Kitchenaid K5A mixer 10 speed only runs on fast, no slow speed

Pull the back off and there will be two screws at the top of the Speed Control Plate and a 3rd screw at the bottom. Tighten the top two screws down. [email protected]. Let me know if it works.

SOURCE: My Kitchenaid K5SS 300 watt standing mixer launches into the highest speed regardless of the speed ....

I had a similar problem where the mixer would also go to fast speed right away. On the back at the top was a screw that was loose. After tightening this screw I had 4 speeds but no stir speed. I unscrewed that screw and a bolt fell out. This bolt went to threads on the inside of the area covered by that back plate. I put that bolt back on and tightened it and the corresponding one on the other side and wala the mixer works perfectly at all speeds. Hope it helps. Make sure mixer is unplugged before attempting anything like this (wires are exposed when the back plate is removed - some kind of flexible circuit board).

SOURCE: Mixer does not function at

Remove the brushes. Two black screws, one on each side. Pay close attention to orientation. MUST INSERT THE SAME EXACT WAY! Use electrical contact cleaner. I said electrical contact cleaner, put the WD40 back in the drawer!!! Using electrical contact cleaner, clean the contacts. Now clean them again, now repeat two or three more times. Spray SOME, meaning a little, into each hole. Reassemble and try it out. If this does not fix the problem refer to the section on removing the cover to access the motor and gears. disassemble clean the motor's brush surface and the contacts. if you don't know what I'm talking about then stop and call a pro.
This is a very common reaccuring problem with these things. Especially when meat grinding or cookie doughing with it. If you move to replace, get a stronger model, like the 500 or the 600. No, I do not sit around repairing mixers all day. I just happen to know a lot about the ones my wife has destroyed. Some two or even three times. after a while it pays to go get the right equipement.

SOURCE: kitchenaid mixer speed

I would recommend that you first check the Hall Effect sensor which determines the mixer’s speed.  I had this exact problem and I actually went out and bought another Hall sensor for about $13.  I replaced the original sensor and made sure that the connection between the sensor and control board was nice and snug. My mixer worked as good as new! But I was curious to know if my original sensor was defective, so I put it back in mixer and again made sure all of the connections were snug and tight. Guess what?  My original sensor also made my mixer work!  There was nothing wrong with the original Hall Effect sensor except that the connection between the control board and sensor was not tight--unfortunately I didn't check the connection before I decided to buy another sensor. My guess is that the connection between the control board and the sensor probably loosens or comes undone over time from use and vibrations. To fix your problem:
1.  Download the mixer parts and diagrams from the Kitchenaid website to see what the Hall Effect sensor looks like. BTW the part number is 9703312.
2.  You'll need a phillips head screwdriver to open up the mixer gear case cover.
3.  Make sure that the connection between the control board and sensor is absolutely tight and snug.
4.  Also, make sure that the orientation of the sensor is correct.  It's difficult to tell which way the sensor should be connected because the control board has three prongs and the sensor can attach facing up or down. After you've made the connection, run the mixer. If it still doesn't work, disconnect the sensor, reconnect it with the prongs facing the opposite direction and try it again.  I actually found the right sensor orientation through a little trial and error.  But by going through this trial and error, I also had my Eureka moment when I realized that the original sensor probably would also work if it were reconnected with correct orientation.  
5.  This whole process probably takes about 10-15 minutes to perform.
6.  Finally, use your common sense and make sure to unplug the mixer before checking, connecting or disconnecting anything.

SOURCE: "Stir" and "2" mix function no longer operate

Yes, your Kitchenaid mixer and be repaired.

You may use the following link to find a Kitchenid certified service center locally to you:

http://caservice.kitchenaid.com/