Electrical; Introduction; System Wiring; Electrical Kits - Carrier Transport Air Conditioning Installation Procedures Manual

5.1 INTRODUCTION

Electrical harness routing is a critical process in the
installation of any transportation air conditioning
system. Pre-planning of the electrical harness path
between components will eliminate encounters with
commonly existing conditions which could result in
electrical system failure. Following proper electrical
harness routing procedures will ensure optimum
system performance and provide for a long lasting and
trouble free installation.

5.2 SYSTEM WIRING

5.2.1 Electrical Kits

The electrical kits provided with Carrier Transport Air
Conditioning systems contain the harnesses/cables
and components necessary to safely connect the air
conditioning to the vehicle power source and
communicate signals between components.
Review the wiring diagram to insure that the kit provided
is the proper wiring kit for your air conditioning system.
NOTE
Wiring diagrams may not always be supplied.
contact the Carrier Transport Air Conditioning
Technical Service Hot Line (1--800-450-2211)
for assistance.
Separate harnesses/cables
appropriate components. Whenever possible route the
harness/cable with the corresponding components
refrigerant hoses.

5.2.2 Protection

Extreme care must be used when wiring a bus. Plan the
routing of the harness prior to installation, being careful
to avoid sources of high heat and sharp edges. If the
wiring is near any heat source it must be shielded with a
heat resistant insulation. When running the harnesses
through sheet metal or other sharp parts of the vehicle
frame the wires must be protected by grommets or tied
off in a manner that prevents chaffing. Where ever
possible the harness should be routed with the
refrigerant hoses (refer to section 4, Hose Routing).
Failure to protect the air conditioning wiring may result in
wiring shorts and system malfunctions.
Most electrical components are sensitive to heat and
environmental conditions. If at all possible they should
be located in a protected area. All exposed electrical
terminals (connectors) should be coated with an
electrical protectant. Circuit breakers should always be
present and located no further than 24 inches (2 feet)
from the vehicles power source or battery. Failure to
follow these precautions could lead to system failure or
in extreme conditions an electrical short-circuit which
could cause a fire.
All connections must be tight and secure. When any
electrical connection is exposed to the elements it
should be coated with an electrical protectant. Ensure a
solid electrical ground to the vehicle chassis. Failure to
ensure tight, protected connections could cause loss of
power to a component resulting in system failure.
Change 07/09
SECTION 5

ELECTRICAL

and route to their
5--1

5.2.3 Dual Systems

When the bus has a dual compressor system care must
be taken to ensure that the electrical system and hose
routing are independent for each side. Test and charge
one system at a time, thus ensuring each system is
functioning properly. Connecting the piping of one
system to the electrical signals from another system will
result in failures to both systems. It is highly
recommended that both ends of the bus harness/cable
assemblies be marked for ease of identification.

5.3 VOLTAGES

Carrier Transport Air Conditioning components are
designed to operate efficiently at 12.5 or 25 volts. For
continued proper operation, all components must have
a proper voltage supply, even during low idle. After at
least 15 minutes of operation, with all accessories and
the air conditioning system(s) on, check the voltage at
the evaporator, condenser, and the compressor.
Voltages less than 12 volts will cause the condenser and
evaporator fans to run slower, resulting in a pressure
build-up, excess heat, and compressor failure. Less
than 12 volts at the compressor may cause clutch
slippage.
Always be sure that the voltages you are working with is
compatible with the air conditioning system you are
going to install (12 Volt--24 Volt).

5.4 COMPONENT CONNECTIONS

The evaporator, condenser and drivers control panel
are pre-wired and are supplied with a short length of
harness (pig-tail). Connect the color wires from the
appropriate harness/cable to the component (pig-tail)
butt connectors (see Figure 5-1).
Evaporator
Harness/Cable
Evaporator
Pig-Tail
Figure 5-1 Harness & Pig-Tail Connections

5.4.1 Evaporator Chassis Ground, Gen 4 (Excel)

After connecting to the evaporator assembly pig-tail and
before routing to the electrical control panel, the
evaporator must be grounded to the vehicle chassis as
follows:
The ground should be as close to the evapora-
tor as possible. Insure that the ring terminal is
grounded to bare metal and coated with an
electrical protectant.
Note
T--311