Heated seats (HS), function - GF91.30-P-0003GK

MODEL 163 as of 1.12.99 with CODE (873) Electrically heated left and right front seats 

Function prerequisites 

• Extended activity module (N10/1)  recognizes "Engine running" via c. 61 e

General 

The heated seats have two heating stages.

Heating stage I "normal heating operation" and heating stage II "quick heat-up".

The heated seats are switched on with the HS switches (S51/1, S51/2).

Function 

The following description applies for vehicles with seat adjustment without memory  . The function on vehicles with seat adjustment with memory  is the same in principle; however, the relays are integrated into the seat adjustment control module with memory (N32/1, N32/2). The extended all-activity module (N10/1)  controls the switch-on duration of the heated seats with two timer modules.

When the switch actuation is recognized the heated seat relay, stage 1 (K59)  and/or heated seat relay, stage II (K59/1)  is actuated by the corresponding timer module. This connects circuit 30 to the heating elements (R13/3, R13/4). 

They are then heated up by the current flowing. When heating stage I  is switched on the heating elements R13/1 and R13/2  or R13/3 and R13/4  are connected in series. The heated seats are switched off automatically after 20 minutes.

When heating stage II  is switched on the heating elements R13/1  and R13/2  or R13/3  and R13/4  are connected in parallel. After 5 minutes the heated seats are switched back automatically to heating stage I.

To reduce wear to the battery it is not possible to switch on the heated seats at battery voltages < 11 V. To reduce wear to the engine it is not possible to switch on the heated seats when the engine fan is defective. If the heated seats were on in one of these cases they are switched off.

These cases are indicated by the LED's in the HS switches (S51/1, S51/2) flashing for 30 s. Then it is necessary to switch on the heated seats again.