LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volvo >> 2003 >> XC70 >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (Alarm System, Control Modules, Engine Management Systems - Design And Function) >> Central Electronic Module (CEM) (2005-2007) >> Function >> Electrical heater with timer function
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Electrical heater with timer function

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Electrical Heater With Timer Function Communication Diagram
GLL146632Courtesy of VOLVO CARS OF NORTH AMERICA.

The desired departure time is set using the steering wheel module (SWM) (3/254).

The central electronic module (CEM) (4/56) calculates when the heater needs to start. The heater starts 2 hours and 45 minutes before the set departure time, irrespective of the temperature. A text message is displayed in the driver information module (DIM) (5/1) when the electrical heater is running.

The accessory electronic module (AEM) (4/78) electrically controls when the heater should be switched on and off. The engine block heater must be connected to a wall socket. The accessory electronic module (AEM) activates a relay which closes the switch for a heater element.