Operation CHARM: Car repair manuals for everyone.

Heating Not Controllable




Heating not Controllable

1. The heating regulates in the direction of maximum cooling and heats only starting from a temperature-switch position of approx. 27.

There is a short circuit in the sensor series.

To check the 3 temperature sensors see "heater heats continuously and can no longer be regulated"

2. Defrost flap not controllable. Pull plug on control motor, switch on ignition and set defrost slide switch to "closed" position.

Voltmeter at term. 1 and term. 2
Reading: approx. 6 V

Voltmeter at term. 2 and term. 3
Reading: approx. 0.1 V

Defrost slide switch in "open" position.
Reading: approx. 6 V

Voltmeter at term.2 and term.4
Reading: approx. 0.1 V

Defrost slide switch in "closed" position
Reading: approx. 10 V

Voltmeter at term. 2 and term. 5
Reading: approx. 0.1 V

Defrost slide switch in "open" position
Reading: approx. 10 V

3. Temperature mixing flap and baffle flap not controllable.

Pull plug on control motor, switch on ignition and set temperature pre-selector to maximum cooling.

Voltmeter at term.1 and term.2
Reading: approx. 6 volts

Voltmeter at term.1 and term.3
Reading: approx. 2.5 volts

Voltmeter at term.1 and term.4
Reading: approx. 10 volt

Set temperature pre-selector to maximum heating
Reading: approx. 0.1 volts

Voltmeter at term. 1 and term.5
Reading: approx. 10 volts

Set temperature pre-selector to maximum cooling.
Reading: approx. 0.1 volts.

4. Footwell flaps not adjustable.

Pull plug on control motor, switch on ignition, and set foot- well slide switch to "closed" position.

Voltmeter at term. 1 and term. 2
Reading: approx. 6 V

Voltmeter at term. 2 and term. 3
Reading: approx. 0.1 V

Footwell slide switch in "open" position
Reading: approx. 6 V

Voltmeter at term. 2 and term. 4
Reading: approx. 0.1 V

Footwell slide switch in "closed" position
Reading: approx. 10 V

Voltmeter at term. 2 and term. 5
Reading: approx. 0.1 V

Footwell slide switch in "open" position.
Reading: approx. 10 V