TM 5-2420-230-24-1
The EGS is in fact an electronic computer and is rather sensitive to supply voltage variations. It
operates well within a large voltage span (9 V DC ⇒ 28 V DC, except when a magneto resistive
sensor is used : 9 V DC ⇒ 16 V DC or 18 V DC ⇒ 28 V DC) but when the supply voltage drops below
the lower limit for too long (milli seconds, example 100 m sec.), it will restart and select neutral or stay
in a reset condition permanently.
So having separate power conductors is specially important for EGS applications.
They assure proper operating conditions for the EGS and prevent that the current flowing through the
EGS (up to 6 amperes) produces voltage drops on supply lines of other sensitive equipment (e.g. VHF
radios etc...).
Finally as the current drawn by an EGS by its nature is 'pulsed' (it's not a continuous current), its
advisable to TWIST power and ground wires just like the twisted pair connections used for sensors.
This significantly reduces the electromagnetic energy radiated by these wires.
Be sure not to reverse the polarity of the connections.
6. OVERRIDE SYSTEM
The EGS (Electronic Control System) is designed to be reliable and fail-safe.
In reality, failures do exist and in case of a failure, the customer wants his vehicle to be functional
again as soon as possible.
If a vehicle is grounded because of a failure in the electronic shift system, the override system can be
activated.
Example of an override system :
Override system of a EGS for a 3 speed transmission
EGS user manual. Page 19 of 25
SPICER CLARK-HURTH
Document reference : egsman4.doc
Revision date: 07/04/97
Ten Briele 3, 8200 Brugge, Belgium
Tel: +32/50/402445
Fax: +32/50/402402
G-21
