Description of the EMM system
The purpose of this document is to describe the specification of the windshield wiper system and how it is controlled by the EMM.
The architecture of windshield wiper control using a low-speed switch via an EMM relay is considered.
System overview
Windscreen wiper motors and windscreen washer pumps
The EMM directly controls the operation of the windshield wiper motor in the following operating modes: intermittent, low speed and high speed. This is the same motor as for the high speed CSW (full class C "5 wire" motor) but with a "low" stop position (at low speed). Compatibility between high speed stopping and low speed stopping is achieved by using adapted dielectric grease.
The operation of the rear window wiper motor is controlled by the VSM. The rear window wiper motor is a "3-wire" motor with a "low" stop position.
The windshield washer pump is controlled directly by the CSW switch. The dual-output pump is used for windshield and rear window washer.
Combination Switch (CSW)
The combination switch (CSW) is a low-speed switch for the windshield wiper and rear wiper and a high-speed switch for the windshield washer. (see picture below).
The windshield wiper motors are powered by BattTempo, and CSW by IgnitionLevel. Therefore, in the state where the wiper contacts of the CSW switch are powered by IgnitionLevel and the vehicle is in the comfort state, the EMM cannot read the inputs of the CSW switch, so the low-speed wiper operation in the comfort mode is not possible, and the service position cannot be reached. If the wiper contacts of the CSW switch are connected to ground, low speed wiper operation and the service position can be available in comfort mode.
Intermittent mode adjustment ring
If the CSW switch is equipped with an intermittent mode adjustment ring, the ring is connected to ground to prevent interference with the detection zone for the intermittent mode position due to voltage changes.
The intermittent mode control ring, connected to ground via the CMS resistor, is less sensitive to voltage fluctuations. The resistance values are selected in such a way as to have separate detection zones without overlapping across the voltage range (9.5 V -16V). The BCM only reads the voltage in the intermittent mode position to determine the ring position.
BCM
The BCM controls the operation of the rear window wiper.
The BCM controls the operation of the rear window wiper motor using an internal relay (REAR Relay). When the rear wiper is commanded to turn on, the BCM closes the relay to supply power to the rear wiper motor until it returns to the AF position.
On some trim levels, the BCM can also control the operation of the rear window wiper motor without the AF position.
If the appropriate configuration is made, then when the driver selects reverse gear, the rear wiper can be turned on while the front wiper is running.
(Original text on the website: LADAMAN)