Waeco MagicSpeed MS-400 Instrucciones De Montaje página 49

MS-400.qxd 24/06/03 15:10 Page 49
Cable harness
If more than two cables run from the brake light switch, then a voltmeter must be used to
identify the necessary cable. One of the two original cables in the brake light switch
should have a continuous positive terminal (terminal 30, 12 V) or a switched positive
terminal (terminal 15). A voltage of +12 V should be adjacent to the brake in operation
with the second original cable. As soon as the brake is released, the cable must conduct
no voltage.
If you are unable to measure any full + 12 V at the brake light switch, then it is possible
that the vehicle is equipped with a computer-controlled braking system. In this case, you
must connect the brown cables as follows: Connect the brown-white cable to a
protected, switched positive terminal (terminal 15). Connect the brown cable to the
original wire which leads to the brake lights. This cable carries + 12 V when the brake is
in operation and 0 V when the brake is released. A possible location where these cables
may be found is directly inside the rear-lights or in the wiring loom to the rear of the
vehicle.
Yellow and blue signal cable
(Connection of the speed- or rotational speed signal). There are two different ways to pick
up a reference signal for the cruise control:
1. Speed signal
The speed signal serves as the real indication of the travel speed. This signal type should
be always used in automatic transmission vehicles, but is also suitable for manual
transmission vehicles, whereby in this case a cut-off must be installed to prevents the
engine over-revving (see page 51).
2. Engine speed (RPM)
The engine speed signal serves to indicate the engine speed (RPM). The vehicle speed
therefore depends on the engine speed as long as the vehicle is travelling in the same
gear. The engine speed signal is only suitable for manual transmission vehicles. In this
case, a cut-off must be installed again to prevent the engine from overrevving
(see page 52).
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