Page 326 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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308 Automobile mechanical and electrical systems

Figure 3.106 General electronic module (GEM) and components. (Source: Ford Motor
Company)

its momentum, after the power is switched off. Being connected to a very low
resistance loads up the ‘motor/generator’ and, when the park limit switch closes,
it stops instantly.
When either the delay contacts or the main switch contacts are operated, the
motor will run at slow speed. When fast speed is selected, the third brush on the
motor is used. On switching off, the motor will continue to run until the park limit

switch changes over to the position shown in Fig. 3.105. This switch is only in
the position shown when the blades are in the parked position.
Many vehicles use a system with more enhanced facilities. This is regulated by
what may be known as a central control unit (CCU), a multifunction unit (MFU) or
a general electronic module (GEM) ( Fig. 3.106 ). These units often control other
systems as well as the wipers, thus allowing reduced wiring bulk under the dash
area. Electric windows, headlights and heated rear window, to name just a few,
are now often controlled by a central unit.
Using electronic control, a CCU allows the following facilities for the wipers:
front and rear wash/wipe
●
intermittent wipe
●
time delay set by the driver
●
reverse gear selection rear wipe operation
●
rear wash/wipe with ‘dribble wipe’ (an extra wipe several seconds after
●
washing)
stall protection.
●

3.4.2 Horns

Regulations in most countries state that the horn (or audible warning device)
( Fig. 3.107 ) should produce a uniform sound. This makes sirens and melody-type