Every so often I get a request for this information I had posted in 2004 about fixing the electronic heater controls in the LE Camrys (and Lexus ES250s) So here is the information once again in an easier to read format.
The problem: No heat or intermittent heat when you slide the slider to the right (red) side.
The cause: The sliding rheostat is often the problem. It leaves an open circuit to the servo that opens and closes the blend door to the heater core, which stays closed, leaving whoever is in the car to freeze.
The fix: Re-solder the contacts on the back of the board.
What you need:
Phillips screwdriver
Continuity tester or Ohm meter
Soldering Iron
First, pull your Climate Control out.
Remove the plastic bezel by unscrewing the two screws at the top of the plastic bezel immediately above the heater control. Carefully pry the bezel out as it is held in by 4 compression clips 2 under the heater control and 2 under the radio/stereo.
The heater control itself is held in by 4 screws 2 on top and 2 on bottom, the heater control will tilt forward from the top, and push inward at the bottom to come out at an angle.
Slide the heat control all the way to the Right/Hot setting. Using a Continuity tester check to see if the two pins circled in orange complete a circuit. If you slide the control over, the resistance of the circuit should get higher (bulb on tester will dim more as it moves to the left/cold) until there is an open circuit. If this works as I describe it, the problem is not with the Climate Control. Otherwise remove the circuit board from the plastic case and fold the connector board over so you can re solder the joints I've circled in orange. (You can also test the circuit from these solder joints to see if the slider is still good.
You can also take a piece of wire, and with the ignition on, jump the corresponding pins in the climate control plug of the cars wiring harness for the heat control. If you can hear the servo motor open the heater door then that part of the circuit is fine. If you can't get your slider control to work, you could put a separate rheostat on that line to operate your heat control separate of the Climate control. If you can't get the servo motor to work that way you will need to check your climate control fuses and servo itself.
Hope this helps, Let me know how it goes.
How to DIY LE electronic heater control fix
Linear Mode
