Connecting Leads; Tracing Ignition Wiring Of The Vehicle; Disconnecting Vehicle Battery - Scania alcolock Installationsanleitung

Connecting Leads

Tracing Ignition Wiring of the Vehicle

Detach cover of the steering column and padded screens to ena-
ble access to ignition switch and wire harness.
If the vehicle wiring is unknown, the respective documents of the ve-
hicle must be consulted or the circuits will have to be traced using a
multimeter or a 12 V resp. 24 V test light:
Switch multimeter to an appropriate DC measuring range.
Place one lead on vehicle ground, for example on vehicle frame.
Test and identify the terminations at the back of the ignition switch
with the second test lead:
switch the ignition switch slowly on to trace the voltage at different
key positions.
Key position
"START"
Lead starter re- Voltage
lay
Lead Voltage
ignition
Lead positive Voltage
supply
NOTICE
Some vehicles have two ignition leads whereof one is without voltage
in key position "START".
Always use the ignition lead that is under voltage in key positions
"START" and "IGNITION".
22
Key position Other
"IGNITION" positions
– – – – – –
Voltage – – –
Voltage Voltage

Disconnecting Vehicle Battery

Disconnect battery ground lead before further work.
NOTICE
Disconnecting the vehicle battery may erase battery dependent in-
strument settings (e. g. the theft code for the radio or the preset sta-
tions). On some vehicles, disconnecting the vehicle battery may turn
the air bag light on, which can be turned off only by the vehicle man-
ufacturer.