tgiaquinto

My daughter's 2004 ES330 has no cabin heat. I've checked everything I can think of.

- Engine temperature is fine. Radiator fluid level good so probably not thermostat.
- Intake and return lines to the heater core are hot so probably not core.
- Blower control and AC working fine. Mode selection working as well.
- No heat either on Auto or Manual mode so probably not the cabin temperature sensor.
- No heat on both sides of cabin in single or dual mode.

I checked both Driver and Passenger side temperature mixing servo units while adjusting the temperature, neither moves. Weird that both would go bad at exactly the same time so thinking it is something else.

Any ideas greatly appreciated. Thanks.

speedkar9

Measure the voltage going to those servo's. If there's nothing, its in the wiring. If there is power, the motor is probably seized or burnt.

Good luck, getting at those servos under the dash can require a lot of dash board disassembly.

tgiaquinto

I'll give it a try. Thanks for the suggestion. I'll let you know how it turns out.

tgiaquinto

Voltage to both was in spec. I took both servo drive units off. Took them apart and cleaned all the potentiometer contacts. Got the passenger side working. The driver side is dead. At least I found the problem and its relatively easy and cheap to fix.

Thanks much for your suggestion.