23
904184 REV A 6/17/11, INST 73-80 CHEV P-UP w/ AC EVAP KIT PG 23 OF 27
SY
M
PT
OM
CO
ND
IT
IO
N
CH
EC
KS
AC
TI
O
NS
NO
TE
S
TROUBLE SHOO
TING INFORMA
TION
1. BL
OWER ST
A
YS ON HIGH
SPEED WHEN IGNITION IS ON
BL
OWER ST
A
YS ON HIGH
SPEED WHEN IGNITION IS ON
OR OFF
2. COMPRESSOR WILL NO
T TURN
ON (ALL O
THER FUNCTIONS
WORK)
SYSTEM IS NO
T CHARGED
SYSTEM MUST BE CHARGED FOR CO
MP
. T
O
ENGA
GE
CHARGE SYSTEM OR B
YP
ASS PRESSURE SWIT
CH
.
CHECK TWO PIN CONNECT
OR A
T ECU HOUSING
TO CHECK FOR PROPER PO
T FUNCTION
, CHECK
V
OL
TA
GE A
T WHITE/ BL
UE WIRE
. V
OL
TA
GE
SHOULD BE BETWEEN 0 AND 5V
, AND W
IL
L V
AR
Y
WITH PO
T LEVER POSTION
.
DISCONNECTED OR F
A
UL
TY THERMIS
TOR WIL
L
CA
USE COMPRESSOR T
O BE DISABLE
D
.
3. COMPRESSOR WILL NO
T TURN
OFF (ALL O
THER FUNCTIONS
WORK)
CHECK FOR F
A
UL
TY A/C PO
T OR ASS
OC. W
IRING
REP
AIR/REPLA
CE PO
T/ CONTROL WIRING
RED WIRE @ A/C PO
T SHOULD HA
VE APPRO
X. 5
V
WITH IGNITION ON
. WHITE WIRE WILL HA
VE
CONTINUITY T
O CHASSIS GROUND
, W
HITE/ BL
UE
WIRE SHOULD V
AR
Y BETWEEN 0V AND 5V WHEN
LEVER IS MO
VED UP AND DOWN
.
REPLA
CE RELA
Y
CHECK FOR F
A
UL
TY A/C RELA
Y
CHECK CONTINUITY T
O GROUND O
N WHITE CONTROL
HEAD WIRE
. CHECK FOR 5V ON RED CONTROL
HEAD
WIRE
.
D
ANGER
- NEVER BYP
ASS SAFETY SW
ITC
H WITH
ENGINE RUNNING
, SERIOUS INJUR
Y CAN
RESUL
T.
CHECK FOR F
A
UL
TY A/C PO
T OR ASS
OC. W
IRING
(NO
T APPLICABLE T
O 3 PO
T CONTROLS
CHECK FOR DISCONNECTED OR F
A
UL
TY
THERMIST
OR.
NO O
THER FUNCTIONS WORK
ALL O
THER FUNCTIONS WORK
CHECK FOR D
AMA
GED PINS OR WIR
ES IN CONTROL
HEAD PL
UG
.
CHECK FOR D
AMA
GED GROUND WI
RE (WHITE)
IN
CONTROL HEAD HARNESS
.
CHECK FOR D
AMA
GED BL
OWER SWIT
CH OR PO
T
AND ASSOCIA
TED WIRING
.
UNPL
UG 3 WIRE BSC CONTROL CONNECT
OR
FROM ECU
. IF BL
OWER SHUTS OFF
, ECU IS EITHER
IMPROPERL
Y WIRED
, OR D
AMA
GED
.
UNPL
UG 3 WIRE BSC CONTROL CONNECT
OR
FROM ECU
. IF BL
OWER ST
A
YS RUNNING
, THE BSC
IS EITHER IMPROPERL
Y WIRED
, OR D
AMA
GED
.
VERIFY ALL PINS ARE INSERTED INT
O PL
UG
. INSURE NO
PINS ARE BENT OR D
AMA
GES IN ECU
.
LOSS OF GROUND ON THIS WIRE RE
NDER
CONTROL HEAD IN OPERABLE
SEE BL
OWER SWIT
CH CHECK PROCEDURE
NO O
THER P
ART REPLA
CEMENTS SHOULD BE
NECESSAR
Y
VERIFY CONTINUITY T
O CHASSIS GR
OUN
D WITH WHITE
CONTROL HEAD WIRE A
T V
ARIOUS P
OINTS
BE SURE SMALL
, 20 GA WHITE GROUND WIRE IS
CONNECTED T
O THE BA
TTER
Y GROUND POST
. IF IT IS
,
REPLA
CE ECU
.
REPLA
CE BSC. (THIS WILL REQUIRE EV
APORA
TOR T
O BE
REMO
VED FROM VEHICLE
.)
CHECK T
O INSURE THA
T NO BSC WIR
ING IS D
AMA
GED
OR SHORTED T
O VEHICLE GROUND
. THE BSC OPERA
TES
THE BL
OWER B
Y GROUND SIDE PWM SWIT
CHING
. THE
POSITIVE WIRE T
O THE BL
OWER WILL
AL
W
A
YS BE HO
T.
IF THE “GROUND
” SIDE OF THE BL
OWER IS SHORTED T
O
CHASSIS GROUND
, THE BL
OWER WILL RUN ON HI.
