1988 PONTIAC FIERO Service Repair Manual

AIR CONDITIONING: COMPRESSOR CONTROLS
C67, ELECTRONIC, V6 VIN S
r---------
OONOTMEASURE
RESISTANCE BLOCK DETAILS
CUT-OUT SWITCH
OPEN
20-28 PSI
CLOSES 41-51 PSI 2960 kPa (430 PSII) CLOSED BELOW
1379 lcPa (200 PSI)
ELECTRONIC
CONTROL
MODULE
(ECM) SOLID STATE DO NOT
MEASURE RESISTANCE
POWER STEERING
CLOSED ABOVE
DISTRIBUTION
- - - -

AIR CONDITIONING: COMPRESSOR CON' .OLS
687, ELECTRONIC, V8 VIN F, V8 VIM 8
A/C CONTROL
OPEN
20-28 PSI
CUT-OUT SWITCH
2960
kPa (430 PSI) CLOSES BELOW
1379 kPa (200 PSI)
RESISTANCE
,8 DK GRNl WHT

AIR CONDITIONING: COMPRESSOR CONTROLS
667, ELECTRONIC, V8 VlN E
FUSE - BLOCK
s201&-~;1 SEE FUSE
.s BRNNVHT ~950 BLOCK DETAILS
AIC CONTROL
HEAO
OPEN 20-28 PSI
CLOSES 45-51 PSI
DK BL:p AIC HIGH 67
2960 kPa (430 PSI) B CLOSES BELOW 1379 kPa (200 PSI)
SEE GROUND DlSFRlBUTlON
v
I
4
ELECTRONIC
CONTROL
MODULE
(ECM) SOLID STATE DO NOT MEASURE
RESISTANCE

AIR CONDITIONING: COMPRESSOR CONTROLS
C67. ELECTRONIC
TROUBLESHOOTING HINTS
Try the following checks before doing the
System Check
.
1 . Check CLSTR Fuse by visual inspection .
2 . Check that the A/C Compressor Clutch con-
nector is firmly seated
.
3 . Check that ground 6112 is clean and tight .
Go to System Check for a guide to normal
Compressor Control operation
.
o Go to System Diagnosis for Compressor Con-
trol diagnostic tests
.
SYSTEM CHECK
Complete the AIC System Check in Section
$A-62 as a guide to normal operation of the
AIC System .
Use the sy&esla Check Table as a guide to
normal operation
of the Compressor Control .
COMPONENT LOCATION Page-Figure
.... ..................... A/C Compressor Clutch (VIN E) Top
RH front of engine 201-
4-A
AIC Compressor Clutch (VIN F) (VIN
..................... ............................ 8) Top RN front of engine 201- 6-A
.... ...................... A/C Compressor Clutch (VIN S) Top LH front of engine 201-
0-B
A/C Compressor Control Relay ..... LN rear comer of engine compartment. on relay
................................. bracket 201- 0-A
Ale High Pressure Cut-Out Switch
(VIN E)
....................... Top RH front of engine. on rear of AIC
.............................. compressor 201- 4-D
AIC High Pressure Cut-Out Switch
(VIN F) (VIN 8)
................. Top RN front of engine. on rear of AlC
.............................. compressor 201- 6-C
A/C Nigh Pressure Cut-Out Switch
(VIN S)
....................... Top LH front of engine. on rear of AIC
.............................. coqressor 201- 0-B
Diode
.......................... Inside AIC Compressor Clutch connector ....... 201- 0-B
Electronic Control Module
(ECM) ... Behind RH side of I/P ...................... 201-12-B
Fuse Block
...................... Behind LH side of IIP. below light switch ....... 201-10-A
Power Steering Switch
............ Lower LH front comer of engine compartment.
.......................... on steering unit 201- 0-A
Pressure Cycling Switch
........... On side of Ale accumulator .................. 201-14-A
ClOO (42 cavities) ................ LN front of dash. left of brake master cylinder .. 201- 0-A
6102 (4 cavities) ................. Center front of dash ........................ 201-14-A
6215 (3 cavities) ................. Center of I/P. behind AlC control ............. 201-14-B
6112 (VIN E)
................... Rear of LH cylinder head .................... 201- 3-C
6112 (VIN F) (VIN 8)
............. Rear of LH cylinder head .................... 201- 7-6
6112 (VIN S) .................... Rear of LH cylinder head .................... 201- 0-C
6118 (VIN S)
.................... Rear of RH cylinder head .................... 201- 1-6
S111 ........................... Engine harness. RH rear of engine compartment 201-
1-A
S117 (VIN
F) (VIN 8) ............. Engine harness. top center rear of engine ....... 201- 7-A
S120
........................... Engine harness. RIP front of dash ............. 201- 2-A
S143 (VIN S)
.................... Engine harness. center front of dash ........... 201- 1-A
S175 (VIN S)
.................... Engine harness. lower LH front of dash ........ 201- 0-A
S177
........................... Engine harness. top RH front of engine ........ 201- 5-A
S201
........................... IIP harness. behind instrument cluster ......... 201-10-A
S204
........................... I/P harness. behind instrument cluster ......... 201-10-A

AIR CONDITIONING: COMPRESSOR CONTROLS
667, ELECTRONIC:
(Continued from previous page)
SYSTEM CHECK TABLE SYSTEM DIAGNOSIS
times
ACTION
1. Turn the Ignition Switch to RUN and start the
engine
Set the
A/C Mode to OFF then to MAX
2. Alternately select OFF and MAX several
Clutch plate movement can be seen on the front
1 ISOLATION TEST (TABLE I) of the compressor pulley
1 I If the clutch does not engage, proceed to step 4 (
EXPECTED RESULT
A click can be heard when the clutch engages
Verify that the clutch engages in MAX
If the clutch operates as expected, continue to
1 St€??J 3 I
V6 VIN S
r Use the isolation Test below to choose the
proper diagnostic tests.
Tests follow the isolation Test.
3. Select MAX mode to engage clutch Check
that air from the coolant fan can move
freely through condensor
Feel the input (cool) and output (warm) pipes to
the compressor
If there is not a wide temperature difference after
the compressor has run for several seconds, see
Section
1B for refrigerant and Compressor
diagnostics
4. Turn off the ignition
Check the refrigerant charge, according to the
procedures in Section
1B
If the refrigeramt charge is low, follow the
procedures in Section
1B for refrigerant diagnosis
If the refrigerant charge is normal, isolate the
conditions using the procedures which follow in
the System Diagnosis
(ISOLATION TEST (TABLE 1) continued on
facing page)
Measure: VOLTAGE
At: AIC COMPRESSOR CONTROL RELAY
CONNECTOR (Disconnected)
Conditions:
ignition Switch: RUN (Engine need
not
be running)
c A/@ Mode: NORM
* Temperature Outside Car: Above 60°F
(16°C)
Refer to System Diagnosis when a result is not normal. Measure
Between
C (PNKIBLK)
& Ground
Correct
Voltage
Battery
For
Diagnosis
Check GAGES
Fuse and PNKi
BLK (39) wire
for an open

(Continued on next page)
AIR CONDITIONING: COMPRESSOR CONTROLS
C67, ELECTRONlG
(ISOLATION TEST (TABLE 1) continued A: ECM COMPRESSOR CONTROL TEST A:
ECM COMPRESSOR CONTROL TEST
If action is correct, do Test A.
from
facing page)
(TABLE 2)
Measure: RESISTANCE
At: ECM CONNECTOR (Disconnected)
Conditions:
r Ignition Switch: OFF
.a Negative Banery Terminal
Disconnected
E (DK GRNI
WHT) &
Ground
(TABLE 1)
Measure: VOLTAGE
At: ECM CONNECTOR (Disconnected)
Conditions:
r Ignition Switch: RUN (Engine not
running)
AIC Mode: NORM
AIC Compressor Control Relay
Connected
Temperature Outside Car: Above 60°F
(I 6°C)
For
Diagnosis
See 1
Measure
Between
B9 on Conn 61
(GRY) &
Ground
Battery
.a If
resistance is correct proceed to Table 3.
1. Check that Power Steering Switch is closed.
If switch is open, replace it. Check for an
open in the GRY (901) wire and
BLKIWHT
(450) wire.
Correct
Resistance
0 ohms For
Diagnosis
See 1
See 2
Measure
Behnreen
B8 on Conn Cl
(DK GRNi
WHT) &
Ground
A2 on Conn
61
(LT BLU) &
Ground
Check
DK
GRNNHT
(59) wire for
an open.
If wire is good,
do Test C
If voltages are correct proceed to Table 2.
1. Check for open in DK
GRNNHT (59) wire.
2. Check for open in LT BLU (905) wire. If wire
is good, replace
AIC Compressor Control
- Relay.
Correct
Voltage
Battery
Battery
If
voltages are correct leave
AlC Com-
pressor Control Relay Connector
disconnected and go to Table
2.
lSOLATlON TEST (TABLE 2)
Connect: FUSED JUMPER
At:
AIC COMPRESSOR CONTROL RELAY
CONNECTOR (Disconnected)
Conditions:
Ignition Switch: RUN (Engine need
not be running)
r A/C Mode: NORM
.a Temperature Outside Car: Above 60°F
(1 6°C)
Jumper
Between
E (DK GRNI
WHT) & A
(DK GRN)
Correct
Action
Clutch
Engages
For
Diagnosis
Do Test B

AIR CONDITIONING: COMPRESSOR CONTROLS
(Continued from previous page) B: AIC COMPRESSOR CLUTCH TEST
A: ECM COMPRESSOR CONTROL TEST
(TABLE
3)
Connect: FUSED JUMPER
At: ECM CONNECTOR (Disconnected)
Conditions: lgnition Switch: RUN (Engine not
running)
@ AIC Mode: NORM
Temperature Outside Car: Above
60 OF
(16°C)
Jumper Correct
Between Action Diagnosis
engages
A2
on Conn
61
(LT BLU)
& Ground
If action is correct but A/C system does not
operate under normal conditions, condition
is due to ECM. Refer to Section 6E for ECM
diagnostics. Compressor
Control Relay
operates and
AfC Clutch
Between 1 Voltage I Diagnosis
Measure:
VOLTAGE
At: COMPRESSOR CLUTCH CONNECTOR
(Disconnected) Ignition Switch: RUN (Engine
not
running)
r AIC Mode: NORM
@ AIC Compressor Control Relay
disconnected
AIC Compressor Control Relay
terminals A and E jumpered
r Temperature Outside Car: Above 60°F
(1 6°C)
See 1
B (DK GRN) & /
Ground I See 1
Measure I Correct
(DK GRN) '1 Battery I See 2 A (BLK)
For
- -
e If voltages are correct but clutch does not
engage, replace the Compressor Clutch.
1. Check for open in DK GRN (959) wire.
2. Check for open in BLK (150) wire.
6: AIC COMPRESSOR FUNCTlON
CONTROL TEST
Measure: VOLTAGE
At: AIC CONTROL HEAD
Conditions: Ignition Switch: RUN (Engine need
not be running)
@ AIC Mode: NORM
Temperature Outside Car: Above
60°F
(16°C)
Measure I Correct
Between Voltage
& Ground
If voltages are correct, go to
61.
1. Check for open CLSTR Fuse or open
For
Diagnosis
See 1
B (LT GRN) &.
Ground -
C1. Remove the connectors from the A/C Pressure
Cycling Switch and the
A/C High Pressure Cut-
Out Switch and connect a fused jumper between
the terminals of the connectors.
If either switch is open, battery voltage will
be present at al E of the AIC Corn-
pressor Control Relay when the jumper is
connected.
Battery
If the Ale Pressure Cycling Switch is open,
refer to Section
1B to check for normal
refrigerant charge. If refrigerant charge is
normal replace the switch. If refrigerant
charge is low, follow procedures in Section
1B for refrigerant diagnostics. Replace
AfC
Control Head
0 If
the NC Nigh Pressure Cut-Out Switch is
open replace
it.

AIR CONDITIONING: COMPRESSOR CONTROLS
667, ELECTRONIC
r If both switches are good but battery volt-
age is not present at the
A/C Compressor
Control Relay, check the wiring between
switches for an open (see schematic).
SYSTEM DlPaGNOSlS
V8 VINF, V8 VIN 8
s Use the Isolation Test below to choose the
proper diagnostic tests.
r Tests follow the Isolation Test.
lSOLATlON TEST (TABLE 2)
Connect: FUSED JUMPER
At:
A/C PRESSURE CYCLING SWITCH
CONNECTOR (Disconnected)
Conditions: Ignition Switch: RUN (Engine need
not be running)
Q NC Mode: NORM
Q Temperature Outside Car: Above 60°F
(1 6°C)
I Jumper I Correct I For
lSOLATlOlU TEST (TABLE 1)
I Measure: VOLTAGE
AIC Mode:
NORM
@ Temperature Outside Car: Above 60°F
(1 6°C)
At:
AIC PRESSURE
CYCLING SWITCH
CONNECTOR (Disconnected)
Conditions:
lgnition Switch: RUN (Engine need
not be running) Between
B (LT GRN) &
A (LT
BLU)
If action is correct, refer to Section 1B for
procedure to check refrigerant pressure. If
refrigerant pressure is
normal, replace the
I (zz) & I Battery I Do Test B I
Measure
Between
A: AIC COMPRESSOR CLUTCH TEST
Action
Clutch
Engages
Diagnosis
Do Test A
Correct
Voltage
.
If voltage is correct, leave Pressure Cycling
Switch disconnected and go to Table
2.
Measure: VOLTAGE
At:
A/C COMPRESSOR CLUTCH
CONNECTOR (Disconnected)
Conditions:
lgnition Switch: RUN (Engine not
running)
0 A/C Mode: NORM
Temperature Outside Car: Above
60°F
(16°C)
For
Diagnosis
(Continued on next page)
Measure
Betvveen
B (DK GRN) &
Ground
B (DK GRN) &
A (BLK)
Q If voltages are correct but clutch does not
engage, replace the Compressor Clutch.
1. Check that A/C Nigh Pressure Cut-Out
Switch is closed (see schematic).
If it is
open, replace it. Check for
an open in the
LT BLU (67) and DK GRN (59) wires.
2. Check for an open in the BLK (150) wire.
Check that ground 6112 is clean and tight.
Correct
\joltage
Battery
Battelr
For
Diagnosis
See 1
See 2