Lull 944E-42 Service Manual - Manual (Page 623)

9.113 Model 644E-42/944E-42 Rev. 6/04
Electrical System
Not
OK
Air Conditioning is
inoperative.
Check wire [BLB] (YEL/GRN)
to blower switch.
With blower switch ON check
wire [BLC] (YEL/ORG) from
blower switch to AC switch for
battery voltage.
Replace blower
switch.
With AC switch ON check
wire [AC2] (BLU) at AC switch
for battery voltage.
Replace AC
switch.
Replace closed
cab harness.
Replace
condenser fans.
If OK
If OK
If OK
If OK
If OK
If OK
Not
OK
Not
OK
Not
OK
Not
OK
Not
OK
Replace closed
cab harness.
If OK
Not
OK
Replace
condenser relay.
Replace closed
cab harness.
Check for battery
voltage at
condenser plug,
pin B.
Replace closed
cab harness.
At compressor,
check wire [CMP1]
(LT GRN/ORG) for
battery voltage.
Replace
thermostat.
Replace
compressor.
Check wire
AC1 (WHT) at
high/low pressure
switch for
battery voltage.
If OK
If OK
If OK
Not
OK
Not
OK
Not
OK
Replace closed
cab harness.
At pressure switch,
check wire [CMP1A]
(LT GRN/ORG) for
battery voltage.
If OK
Not
OK
Replace pressure
switch.
Replace closed
cab harness.
Check thermostat at wire
AC1 (WHT) for battery
voltage. Thermostat closed
if temperature is above
35° F (1.7° C).
Check ground at
condenser plug,
pin C.
Check for
battery voltage at
condenser plug,
pin A.
Check for battery
voltage at internal
condenser relay,
pin 87.
Condenser Circuit Check Compressor Circuit Check
Before troubleshooting any
electrical circuit, ALWAYS
begin by checking the
following:
1. Fuses.
2. All connections relating to
circuit are clean and tight.
3. All grounding straps are
intact and securely
fastened, refer to Section
9.1.12, “General Overview
(Vehicle Ground Strap
Locations).”