Residual heat

The residual heat function makes it possible to use engine heat for heating the interior of the vehicle when the engine is not running.

With the ignition switched off and at an outside temperature of < 15^o C, the function can be called up with the residual heat function button in the operating unit for a maximum time of 15 minutes. The system voltage is monitored and switched the function off at < 11.4 V. After being switched off by the undervoltage, the system is not switched on again even if the voltage exceeds 11.4 V once again.

Switch-on conditions for the residual heat function:

• Residual heat function button ON
  and
  
• outside temperature < 15^o C
  and
  
• engine temperature once > 70 ^o C
  and
  
• ignition key position terminal R or OFF
  and
  
• 15 minutes after terminal 15 OFF not yet elapsed
  and
  
• system voltage > 11.4 V
  
  

Switch-off conditions for the residual heat function:

• Residual heat function button OFF
  or
  
• Terminal 15 ON
  or
  
• system voltage < 11.4V
  

The residual heat function can be activated in ignition lock position OFF or at terminal R. Various settings are possible dependent on the ignition lock position.

Statuses at ignition lock 1:

• Operating unit active
  
• Temperature control adjustable
  
• Flap program adjustable
  
• Blower adjustable
  
• Function lights ON
  
• Right-hand button pad not active (defrost, rear window defogger, recirculated air/AUC and air conditioning)
  

Statuses at ignition lock 0:

• Operating unit not active
  
• Temperature control is set at ignition OFF
  
• Flap program and blower setting as for independent heating
  
• Only function light of residual heat function button active