Temperature Door and Heater Output Activation, Checking

Temperature Door and Heater Output Activation, Checking

• On Audi TT without A/C (just heating), only one temperature door motor is installed. Both temperature doors for the left and right sides are connected in the heater air distributor housing via a shaft and moved together by the Left Temperature door Motor (V158). Refer to=> [ Heater Electrical Attachments ] Heater Electrical Attachments.

• Vehicles without A/C do not have a temperature sensor. The outflow temperature is not controlled. The Left Temperature Door Motor (V158) is placed in a position calculated according to the temperature setting on the temperature rotary switch - A - and the programmed motor stop values by the Climatronic control module (J255).






• If coolant circuit is not completely bled after filling, air may accumulate in heater core of heater, thus reducing heating performance, additional noises may occur or customer may complain of different air temperatures flowing out of vents at driver's side and front passenger's side.

Corrective action:

- Perform long road test at increased engine speed (at least 10 minutes, engine speed greater than 2500 RPM). Select a low gear during the test to prevent excessive vehicle speed.

- If customer complains of poor heating performance at specific engine speeds, check incorporation of heater core of heater in the coolant circuit. If both coolant hoses (supply and return) of engine are interchanged, coolant is flowing in the wrong direction through the heater core.

• Heat output and temperature door activation, checking refer to => [ Heat Output and Temperature Door Activation, Checking ] Heat Output and Temperature Door Activation, Checking.