jlaguard

Do you feel that's a reasonable price from the dealer?

500 parts, 600 labor

If your temp guage reads normal then its not the thermostat. Sounds like the dealer is right, seems your valve is not switching over to allow hot water into the lines.

Do you advise I should go with the repair at the dealer or somewhere else? The dealer said it would cost 1100 to fix the motor

I have a 2001 RX300 with >100K Mileage. Recently my heater has stopped functioning. The AC works at all temperature levels from min-max and the fan output seems normal. At the time it stopped functioning I remember smelling a slight burnt smell and actually a plume of smoke came from the vents. Please note the seat warmers still heat up.

I took it into two different Lexus Dealers who both said I needed to replace my servo motor. Does this add up?

I was thinking maybe it was a bad thermostat or bad heating coil but I don't know much about cars to make that statement with any degree of certainty.