194001432 - E3030 DEMISTING REARSCREEN AND REAR VIEW MIRRORS - DESCRIPTION

In the case of poor visibility it is possible to activate the demisting of the rearscreen, the exterior rear view mirrors and the windscreen jets.The heating resistances for these components absorb a considerable amount of energy and are therefore controlled and, possibly, deactivated after they have been working for a certain length of time: the demisting is subject to a delay timer, managed by the Body Computer, according to the following logic:- key ON (INT/A from steering lock control unit);- engagement signal coming from the special button in the climate control system control panel.Under these circumstances the resistances remain supplied for a maximum of 20 minutes, then the supply is cut off.The supply is cut off in the following conditions:- key OFF or removed;- disengagement signal from the button;- battery voltage below 8.5 V;- after the first 15 minutes of operation if the engine speed is below 960 rpm.With the defrosting on the warning light in the climate control system controls also comes on.The activation timer (20 minutes) is set again each time the button is operated.The climate control system control unit logic also intervenes with the "MAX-DEF" command in accordance with the logic described previously.The "MAX-DEF" function lasts for 3 minutes starting from when the engine temperature exceeds a certain limit.
the deactivation of the MAX-DEF control only causes the switching off of the heated rear windscreen if the command to switch it on came from the MAX-DEF button; if, on the other hand, the command was given via the heated rear windscreen button, it remains on)
The rearscreen defrosting circuit is controlled by the heated rear windscreen relay and protected by a specific fuse, located in the junction unit under the dashboard. This circuit is controlled by the logic described above directly by the Body Computer.The defrosting circuit for the door mirrors, on the other hand, is protected by another fuse in the junction unit under the dashboard and is controlled by the door control units, in accordance with the logic transmitted by the Body Computer via the CAN.