Residual Heat Utilization, Basic Function - GF83.40-P-1005A

Model all (CAR) 

Overview 

This document contains information on:

• General 
• Function requirements 
• Function 

General 

The function "residual heat" is only available on vehicles with at least one of the following equipment items:

• Climate control with at least 2 temperature zones
• Pre-installation for taxi/rental car
• Alternative drive

It enables the vehicle to be heated for a certain period of time even after the ignition is switched off. To this end, the residual heat of the combustion engine is directed into the vehicle interior. The residual heat utilization function is controlled by the climate control control system.

Function requirements 

• Climate control switched on
• Engine switched off

Function 

After switching on the residual heat utilization function on the air conditioning control panel, the coolant circulation pump is switched on. This routes the coolant which is still warm (residual heat) through the heater core. In addition, the blower motor is actuated at the lowest stage. The air drawn in by the blower motor flows through the heater core and warms up there. The warm air flow now flows to the respective air outlets.

The residual heat utilization function switches off after approx. 30 min or when the on-board electrical system voltage drops below a certain value.

On model 247 as of model year 2023 with code 581 (Automatic air conditioning), residual heat utilization is no longer required.