PREVOST H3-41 Maintenance Manual page 201

NOTE
All modules including Wake-up modules and MCM have to be powered OFF prior to probe the DL0
(BBUS MUX) lines with an ohmmeter.
Probing the resistance between the DL0H and DL0L wire is a useful method to localize short circuits or
open circuit on the DL0 (BBUS MUX) network. However, when doing so, make sure none of the
modules connected to the DL0 (BBUS MUX) line are powered, including wake-up powered modules
and battery direct supply module (MCM). Otherwise the measured value is invalid and will always show
OL (Open Load). This is because the modules are applying a voltage on the DL0 (BBUS MUX) lines
and this is fooling the ohmmeter.
Proceed as follow when probing the DL0 (BBUS MUX) line with an ohmmeter in order to get a valid
reading:
Turn ignition key to the OFF position.
•
Set the main electrical shut-off switch to the OFF position to turn all Wake-up modules power
•
to OFF.
Trip circuit breakers CB2 and CB6 to remove direct battery power from the MCM.
Use the spare "FRONT ELECTRICAL COMPARTMENT to pneumatic accessories panel" CAN
Pneumatic accessories panel: disconnect C13 and connect C13S pin housing to C13 socket.
FRONT ELECTRICAL COMPARTMENT: Disconnect C5 and connect C5S socket housing to C5 pin housing.
PA1621 Maintenance Manual All Series | Revised Sept 2019
SECTION 06: ELECTRICAL
37