If your fan speeds are not all there or just totally gone the first thing to suspect is the set of resistors that control the fan speeds. There is a SOGI Tech Tip on this but they give instructions on how to repair it. I found that to be a bit silly since it was only about $23 for a new one all together. Maybe they were more expensive back then, but I would just replace it if things go wrong. My Toyota dealer had them in stock so that meant that they probably belong to a whole range of Toyota cars since they only stock parts commonly ordered parts there. In fact mine wasn't even broken, I have had intermittent problems so I just decided to replace it to help track down the problem. My old one was all corroded and the new one was shiny and happy. This should take you all of 20 minutes to do.
| Tools: |  |
Philips screw driver |
| Materials: | Resistor (87138-24030) |
Instructions
| 1. |  Remove 3 philips screws from glove box under cover and remove. |
| 2. |  Remove the connector and phillips screw from the resistor pack and carefully remove it. |
| 3. | Carefully install the new resistor pack and tighten the philips screw then reconnect the connector. |
| 4. | Turn the ignition to on and test all the fan speeds, they should work properly now. |
| 5. | Replace the glove box undercover. |