Electric Motor Test Sequence - PREVOST H3-41 Maintenance Manual

SECTION 06: ELECTRICAL
Upper windshield wipers switch, 2 positions
The following inputs, either certain options or
sensors which are difficult to activate, are not
supported by the switch/sensor test:
• Service chime enable switch,
• Horn selector switch,
• Outside rear view mirror heat,
• Mirror control switches,
• Low-buoy switch,
• Starter sensor,
• ABS warning input,
• WCL switch,
• Driver's power window switch,
• Alternator sensors 1 & 2,
• Retarder active signal,
• Radiator fan speed 1 & 2 signals.
In test mode, with the parking brake applied and
the passenger set point set to a value higher
than 64°F (18°C), the circulator pump is not set
to OFF as it would normally do when the outside
temperature gets above 50°F (10°C). This
feature allows verification of the pump when
inside a garage. This is also useful when
working on the heating system to remove air
pockets trapped in the system.
When performing an A/C cooling test and having
the water pump shut off is required, initiate the
multiplex input test mode. While in this mode,
just set the passenger set point temperature to
the minimum 64°F (18°C) to shut off the pump.
4.2

Electric Motor Test Sequence

This test mode allows testing of the electric
motors, the A/C compressor clutch and unloader
and the HVAC system solenoid valves without
the need to have the engine running. Note that
while in test mode, the engine cannot be started.
Prerequisite conditions for the motor test mode:
A. The battery charger must be connected to a
110-120 volt power supply. If not, the test
will be interrupted when the voltage drops
below 24.4 volts,
B. Engine not running,
C. Parking brake applied,
28 PA1621 Maintenance Manual All Series | Revised Sept 2019
DANGER
Before starting the test sequence, make sure
that no one is doing maintenance in the
evaporator compartment,
compartment or close to the CAC & radiator
electric cooling fans.
NOTE
The back-up alarm will sound (beep) ten (10)
times prior the test starts to warn the persons
who do work on the vehicle. Moreover, the
alarm will beep to tell the person conducting
the electric motors test sequence to move to
the next test location on the vehicle.
To enter this mode:
• Using the dashboard
DIAGNOSTICS menu and press ENTER
button ;
• Select VEHICLE TEST, press ENTER button
then select START ELECTRIC MOTORS
TEST and press ENTER button to initiate the
test mode for electrical motors;
• Ten (10) beeps can be heard indicating the
motor test mode has started.
Using the test mode:
• During the entire test, the telltale panel
audible alarm gives a signal each second to
remind that the motor test mode is underway.
the condenser
DID, select