Utilimaster Aeromaster 2019 User manual

1 of 34
03103436-A10030 Rev. B
Service
Guide
Contents
Safety Considerations...............................................................................................................2
AC System Overview.................................................................................................................3
Procedures.................................................................................................................................4
Blower Motor..........................................................................................................................4
Control Head..........................................................................................................................5
Condenser..............................................................................................................................7
Dryer ......................................................................................................................................7
Binary Switch .........................................................................................................................9
Hose Replacement...............................................................................................................10
Pressure Transducer............................................................................................................12
Plenum.................................................................................................................................13
Internal Servo Motors...........................................................................................................17
Passenger Side Vent ...........................................................................................................20
Heater Valve and Servo Motor.............................................................................................20
Evaporator and Heater Core Assembly ...............................................................................22
Heater Core..........................................................................................................................27
Evaporator Coil ....................................................................................................................31
Test System .............................................................................................................................34
Heater with Air Conditioning
2019 and Later Aeromaster
NOTICE
The information in this document is generic. Details in illustrations and procedures
may di󰀨er from those in your vehicle. Because Utilimaster manufactures many di󰀨erent
customized vehicle bodies, this document cannot list and illustrate every possible option for
every vehicle. Nevertheless, the most common body options are described here. Use this
information as a guideline where it applies. Refer also to the separate chassis operator’s
guide supplied by the chassis manufacturer.

2 of 34
03103436-A10030 Rev. B
NOTICE
Read and understand the instructions before starting work.
Keep all fasteners for reinstallation unless otherwise noted.
This document does NOT address removing work tables, cup holders, or other optional
equipment to gain access to the plenum.
!
WARNING
Avoid breathing AC refrigerant and lubricant vapor or mist. Utilimaster recommends that a
licensed automotive air-conditioning specialist work on the vehicle’s air-conditioning (HVAC)
system.
Operate the engine only in a well-ventilated area.
Use safety stands and/or wheel blocks whenever you are underneath the vehicle.
Always wear safety glasses and other protective equipment as appropriate to the process.
Become familiar with all warning labels.
Be sure that the ignition switch is O󰀨 unless otherwise required by the procedure.
Put the transmission in Park (if it is an automatic) and set the parking brake before working on
the vehicle.
Avoid contact with hot metal parts, such as the radiator or exhaust system.
Do NOT smoke while working on the vehicle.
Always remove rings, watches, hanging jewelry, and loose clothing before working on a
vehicle. Tie long hair securely behind your head. Keep yourself and your clothing away from
the radiator fan, belts, and any moving parts when the engine is running.
Keep hands and other objects clear of the radiator fan blades. The electric fan can start at any
time even though the ignition is O󰀨. Disconnect the fan when working under the hood.
Batteries that are improperly connected can potentially explode and discharge acid, causing
vehicle damage and personal injury. Refer to the chassis manufacturer’s instructions. Battery
posts and related accessories may contain lead and lead compounds. Wash hands after
handling. Always wear proper protective equipment when working around batteries.
Safety Considerations

3 of 34
03103436-A10030 Rev. B
AC System Overview
EVAPORATOR
COMPRESSOR
CONDENSER
BLOCK HOSE
RECEIVER/
DRYER
CHARGING PORT
CONDENSER
COMPRESSOR
HOSE
LOW PRESSURE
SWITCH
EVAPORATOR
HOSE
DRYER HOSE
TRANSDUCER
PORT
BINARY
SWITCH
CONDENSER
BLOCK HOSE
RECEIVER/
DRYER COMPRESSOR
HOSE
LOW PRESSURE
SWITCH
TRANSDUCER
PORT
BINARY
SWITCH
RESISTOR THERMOSTAT
AC system overview (plenum omitted for clarity)

4 of 34
03103436-A10030 Rev. B
Procedures
Blower Motor
Removal
1. Disconnect the wire harness.
2. Remove the (6) screws to the blower motor.
3. Disconnect the vent hose.
Blower motor
Installation
1. Connect the vent hose.
2. Secure the blower motor with (5) screws. Secure the wire harness and fasten wire harness clamp
with (1) screw and at washer.

5 of 34
03103436-A10030 Rev. B
Control Head
Removal
NOTICE
Depending on the model, it may help to remove the dash cover to access the HVAC controls.
1. Remove the (4) screws and nuts or the HVAC controls.
2. Unplug the fan switch from the HVAC controls.
Control head connections
(A) fan switch, (B) temp connector, (C) mode connector, (D) recirculation connector,
(E) max AC connector, (F) backlight socket
B
CD
E
A
F
3. Disconnect (4) wire harness connectors.
4. Remove (2) backlight bulbs with 1/2 turn.
Installation
1. Secure the backlight bulbs into the control head with 1/2 turn.

6 of 34
03103436-A10030 Rev. B
NOTICE
Ensure that the wire colors match at the connectors.
2. Connect the (4) wire harness connectors to the control head.
Ensure that the male and female wire colors match the adjoining harnesses
3. Plug in the fan switch connector.
4. Attach the control head to the dash panel with (4) screws and nuts.

7 of 34
03103436-A10030 Rev. B
Condenser
NOTICE
The condenser is a chassis component. Refer to the chassis service information or your local
dealer.
Dryer
Removal
NOTICE
It is strongly recommended that the dryer and expansion valve be replaced whenever the
system is opened for service.
1. Evacuate the air-conditioning system of all refrigerant.
2. Remove horns, air rams and any other obstructions and set aside.
3. Disconnect air-conditioning hoses from dryer.
4. Remove binary switch.
5. Remove (2) screws from dryer mounting bracket and set aside.Discard dryer.
(A) Horn fasteners, (B) dryer binary switch, and (C) mounting screws
B
C
A

8 of 34
03103436-A10030 Rev. B
Installation
NOTICE
It is strongly recommended that the dryer and expansion valve be replaced at the same time.
1. Install binary switch.
2. Lubricate (2) new O-rings with mineral oil and attach to dryer.
3. Secure dryer hoses.
4. Torque nuts.
5. Secure dryer with (2) screws.
6. Charge air-conditioning system with refrigerant.
7. Start vehicle and check air-conditioning performance.
Dryer location under the hood

9 of 34
03103436-A10030 Rev. B
Binary Switch
The binary switch is located on the dryer. The switch has two functions: high pressure cut-out and low
pressure cut-out.
Removal
1. Disconnect wire harness.
2. Remove switch by turning counterclockwise and set aside.
Installation
1. Lubricate rubber seal inside switch with mineral oil.
2. Secure switch by turning clockwise.
3. Connect wire harness.
Binary switch on dryer

10 of 34
03103436-A10030 Rev. B
Hose Replacement
Example of replacement of air-conditioning hose between the compressor and the evaporator.
NOTICE
The hose connection at the compressor may be easier to access with the wheels turned
completely to the right.
1. Remove the keys from the ignition.
2. If needed remove the front passenger’s side splash guard and set aside.
Remove splash guard
3. Evacuate the air-conditioning system of refrigerant.
4. Remove the hose between the compressor and evaporator.
5. Remove low-pressure switch.
6. Install low-pressure switch to replacement hose.
7. Torque switch.
8. Install replacement air-conditioning hose to evaporator.
Low pressure switch on AC hose AC hose connections at the evaporator