Lull 944E-42 Service Manual - Manual (Page 178)

Electrical System
9-20 944E-42
9.10 CAB HEATER AND FAN
9.10.1 Cab Heater Controls
Note: If the suspect component is found to be within the
heater box, the heater box must be removed as a
complete unit and replaced.
The cab heater and air conditioning controls (1) are
located in the lower bank of switches on the right side of
the dash. From left to right the control panel consists of:
a variable speed fan control (2), an A/C on-off switch (3)
and a temperature control (4).
a. Cab Heater Controls Removal
1. Park the machine on a firm, level surface, level the
machine, fully retract the boom, lower the boom,
place the transmission control lever in
(N) NEUTRAL, engage the park brake and shut the
engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
3. Open the engine cover. Allow the system fluids to
cool.
4. Properly disconnect the batteries.
5. Remove the setscrew from the variable speed fan
control knob or temperature control knob.
6. Remove the screws and backing locknuts from the
cab heater and fan control panel.
7. Pull the control panel out from the dash panel, and if
removing variable speed fan control, remove the cab
harness connector.
8. If removing the temperature control knob, disconnect
the cable connector and remove control knob.
9. Remove the locknut from the suspect control shaft.
10. Remove the control from the panel.
11. If removing the air conditioning rocker switch, label
and disconnect the cab harness connector. Carefully
pry the switch out of the mounting hole.
b. Disassembly
DO NOT disassemble the cab heater and fan controls.
The controls are not serviceable. Replace controls if
found to be defective.
c. Installation and Testing
1. Check that the variable speed fan control is in the
OFF position.
2. If installing the temperature control, attach the
control cable to the back of the control.
3. Insert the control shaft through the panel, ensuring
that the knob is in the VERTICAL position.
4. Install the locknut on the shaft and tighten.
5. Install the setscrew securing the knob to the control.
6. Snap the air conditioning rocker switch into the
mounting hole on the control panel. Connect the cab
harness connector to the back of the rocker switch.
7. Install the screws and backing locknuts securing the
control panel to the dash panel.
8. Properly connect the batteries.
9. Turn the ignition key to the ON position and check
the fan speeds. If further repair is needed, refer to
Section 9.5, “Electrical Schematics.”
10. Start the machine and allow engine to warm to
operating temperature. Check heat control at
different levels.
11. Close and secure the engine cover.
MU6940
1
2
3
4