1988 PONTIAC FIERO ignition

HEATER
(A: BLOWER SWITCH TEST continued from
previous page)
1. Check/repair BRN (50) wire for an open
(see schematic).
3: BLOWER RESlSTORS TEST
Measure: VOLTAGE
At: BLOWER RESISTORS CONNECTOR
(Disconnected)
Conditions:
* lgnition Switch: RUN
Blower Switch: LO
Measure Correct
For
Between Voltage
Diagnosis
[ 0 Blower Switch: MED
A(LTBLU' I Battery I See 2 & Ground I
2 BLOWER MOTOR TEST
R CONNECTOR
(Disconnected)
Conditions:
* lgnition Switch: RUN
ORN wire & Battery Ground See 1
ORN wire & I Battery I See 2 BLK wire I
0 If
all results are correct, replace the
Blower Motor.
1. Perform Blower Switch Test. If Blower
Switch is OK,
check/repair ORN (52)
wire for an open (see schematic).
2. Check BLK (150) wire for an open (see
schematic).
CIRCUIT OPERATION
The Blower Motor delivers air to the inte-
rior of the vehicle. Its speed is controlled by
the Blower Switch and the Blower Resistors.
When the Ignition Switch is in RUN, battery
voltage is applied to the Blower Switch. With
the Blower Switch in LO, voltage is applied
across both Blower Resistors and the Blower
Motor. The Blower Motor runs at its slowest
speed. With the Blower Switch in MED, one of
the Blower Resistors is bypassed and the
Blower Motor runs faster. When the Blower
Switch is set to
HI, battery voltage is applied
directly to the Blower Motor and the Blower
Motor runs at its fastest speed.
0 If all results are correct, replace the
Blower Resistors.
1. Check/repair YEL (51) wire for an open
(see schematic).
2. Check/repair LT BLU (72) wire for an
open (see schematic).

DEFOGGER
TROUBLESHOOTING HINTS
e Try the following checks before doing the
System Check.
1. Check the PWR ACC Circuit Breaker by
operating the Power Door Locks or Power
Seats (if equipped).
2. Check the Gages Fuse by observing that the
Instrument Cluster Lights.
3. Check ground 6200 by observing that the
Cigar Lighter operates normally.
4. Check that the connectors on the Defogger
and the Defogger Timer-Relay are properly
mated.
5. If one or more of the grid lines do not heat,
refer to the Body Service Manual (Section
2) for repair procedures.
e Go to System Check for a guide to normal
operation.
a Go to System Diagnosis for diagnostic tests.
COMPONENT LOCATION Page-Figure
............ ............. Defogger Timer-Relay Behind
RH side of IIP, near ECM 201-1 1-D
..................... Fuse Block. Behind LH side
of I/P, below light switch. ...... 201-10-A
.................. 6201 (1 cavity) LH
shroud, near center access hole
.......................... 6200 Behind IIP, left of steering column ............ 201-10-16
.......................... 6322 Rear of car, near RH hatch support bracket. .... 201-15-D
.......................... S204. IIP harness, behind instrument cluster. ........ 201-10-A
.......................... S205. IIP harness, behind instrument cluster. ........ 201-10-A
.......................... S233. IIP harness, above Fuse Block. ............... 201-10-A
.......................... S327. Defogger harness, behind LR side of rear seat
SYSTEM CHECK
e Use the System Check Table as a guide to
normal operation. Refer to the diagnosis
given if other results occur. The actions must
be
pedormed in the order shown.
Tests follow in System Diagnosis.
SYSTEM CHECK TABLE -- -
ACTION NORMAL RESULT FOR DIAGNOSIS OF OTHER RESULTS
1. Turn the Ignition Switch to RUN, and de-
press the Defogger Control Switch.
2. Depress the Defogger Control Switch again
3. With the Defogger ON, depress the Defog-
ger Control OFF Switch
I
A. The switch button returns to the rest posi-
tion, and the ON Indicator in the center of the
Defogger Control lights
B. The Defogger grid removes fog from the
rear window
C. The ON Indicator and the Defogger turn
off after approximately
10 minutes
The ON Indicator and the Defogger turn on
After approximately
5 minutes, they turn off
again
The ON Indicator and the Defogger turn OFF Do
Test A
Do Test B
Do Test D
Replace the Defogger Timer-Relay
Do Test B
(Continued on next page)

DEFOGGER
SYSTEM DIAGNOSIS
Do the tests below when directed by the
System Check.
A. DEFOGGER TIMER-RELAY INPUT
VOLTAGE TEST
At: DEFOGGER TIMER-RELAY CONNECTOR
(ORN/ I Battery
BLK) &
I Ground I
(PNK/ I Battery I See 2 BLK) & I
Ground
If all the voltages are correct, go to Test
B.
1. Check the ORN/BLK (60) wire for an
open (see schematic). If the wire is OK,
check the PWR ACC Circuit Breaker.
2. Check the PNK/BLK (39) wire for an
open (see schematic). If the wire is OK,
check the Gages Fuse.
-RELAY CONNECTOR
Ignition Svvitch: RUN
A (PPLIWWT) Test Lamp
& Ground does not light See 1
If all the
results are correct, do Test D.
1. Replace the Defogger Timer-Relay.
2. Check the
BLKIWKT (150) wire for an
open (see schematic). Check that ground
6200 is clean and tight.
3. Check the LT BLU (292) wire for an open
(see schematic).
If the wire is OK, do Test
6.
4. DoTest C.
B: DEFOGGER TIMER-RELAY TEST 6: DEFOGGER CONTROL VOLTAGE
TEST
At: DEFOGGER CONTROL CONNECTOR
e lgnition Switch: RUN
Defogger Switch: ON (HOLD)
a Headlight Switch: PARK (Maximum
I C (GRY) &
D (BLK) Battery

DEFOGGER
r If all the voltages are correct, and the
Defogger still does not operate properly,
do Test D.
1. Check the PNK/BLK (39) wire for an
open (see schematic). If the wire is OK,
check the Gages Fuse.
2. Replace the Defogger Control.
3. Check the PPL/WHT (293) wire for an
open (see schematic). If the wire is OK,
do Test B.
4. Check the INST LP Fuse. Check the
GRY
(8) wire for an open (see
schematic).
5. Check the BLK (150) wire for an open
(see schematic). Check that ground
6200 is clean and tight. Replace Panel
Light if wire and ground are OK.
D: DEFOGGER TEST
With the Ignition Switch in RUN, and the
Defogger Switch pressed
ON, connect one lead
of a test lamp to ground. From inside the car,
lightly touch the other lead to each grid line,
and slowly move it along the length of the grid.
The brilliance of the test lamp bulb should
increase as the test lamp is moved from left
(Passenger's side) to right (Driver's side).
0 If the test lamp does not light along any one of
the grid lines, check
PPLIWHT (2931, PPL
(192) and BLK (192) wires to the Defogger
Control for an open
(see schematic). If OK, do
Test
E.
If the test lamp bulb shows full brilliance at
both ends of the grid, check the BLK
(1 50)
wire for an open to ground (see schematic).
e If the test lamp suddenly lights as it is moved
along the grid, a break in the continuity of the
grid line exists. Refer to the
GM Body Service
Manual for grid line repair procedure.
E: DEFOGGER LAMP TEST
CH SUPPORT ARM
Ignition Switch: RUN
LH Hatch
Support Arm
(Braided Test
Lamp
lights See
1
Wire) &
Ground
(see
schematic)
(Continued in next column) (Continued
from previous column)
See 2
Arm
(Braided
Wire) (see
schematic)
I
If all the results are correct, refer to the
GM Body Service Manual Section 2 for
grid line repair.
1. Do Test B.
2. Check the BLK (150) wire for an open
(see schematic). Check that Ground
6322 is clean and tight (see schematic).
CIRCUIT OPERATION
With the Ignition Switch in RUN, voltage
is applied to the Defogger Control. When the
Defogger Control Switch is pressed ON, volt-
age is then applied to the Defogger
Timer-
Relay. The contact closes which provides volt-
age to the ON Indicator and the Defogger.
The rear window will become warm to remove
the fog from the surface of the window.
The contact in the Defogger Timer-Relay
will stay closed until the Defogger OFF
Switch is pushed, or the timer cycle is
complete.
(Continued on next page)

DEFOGGER
(Continued from previous page)
The first time the Rear Defogger Switch is
pushed in, the Defogger Timer-Relay will al-
low the Defogger to operate for approximately
10 minutes. Each time after the rear Defogger
Switch is pushed in, the Defogger Timer-Re-
lay will reset to operate for approximately
5
minutes. The Defogger Timer-Relay will reset
to 10 minutes when the Ignition Switch is
turned OFF and then back to the
RUN
position.
The timer also shuts off at any time when
the Defogger Control OFF Switch is de-
pressed. In order to reset the Defogger
Timer-
Relay for the initial 10 minute time interval,
the Ignition Switch must be turned OFF and
then back to the
RUN position before activat-
ing the Defogger.

AIR CONDITIONING: BLOWER CONTROLS
C60, MANUAL
TROUBLESHOOTING
HINTS
Try the following checks before doing the
System Check.
1. Check the HTR A/C Fuse by visual inspection.
2. Check that ground
6112 is clean and tight.
3. Check that Blower Motor connectors and
Blower Relay are mated correctly and firmly
seated.
Go to the A/C System Check in 8A-62 for a
guide to normal operation.
Q Go to System Diagnosis for diagnostic tests.
SYSTEM DIAGNOSIS
Do the tests listed for your symptom in the
Symptom Table below.
Q Tests follow the Symptom Table.
SYMPTOM TABLE
SYMPTOM
Blower runs all the
time (Ignition OFF)
Blower run
all the
time (Ignition OFF)
Blower will not run
in any mode
No Lo speed
operation
COMPONENT LOCATION Page-Figure
Blower High Speed Relay.
......... RH front of dash, near Blower Motor ..........
Blower Motor (With Ale) .......... RH front of dash. ..........................
Blower Resistors (With AIC) ....... RH front of dash, behind strut tower ..........
Fuse Block. ..................... Behind LH side of IIP, below light switch. ......
Fusible Link B (VIN E). ........... Lower RH side of engine, at Starter Solenoid. ...
Fusible Link B (VIN F) (VIN 8) ..... Lower RH side of engine, at Starter Solenoid. ...
Fusible Link B (VIN S). ........... Lower RH side of engine, at Starter Solenoid. ...
(2102 (4 cavities) ................. Center front of dash. .......................
6115 (1 cavity). .................. Center front of dash. .......................
(2202 (1 cavity) .................. Behind. center of IIP, near control head. ........
6112 (VIN E) ................... Rear of LN cylinder head. ...................
6112 (VIN F) (VIN 8) ............. Rear of LH cylinder head. ...................
6112 (VIN S). ................... Rear of LH cylinder head. ...................
Slll ........................... Engine harness, RH rear of engine compartment
S117 (VINE)
.................... Engine harness, RH front of dash. ............
S117 (VIN F) (VIN 8) ............. Engine harness, top center rear of engine. ......
S119. .......................... AIC harness, RH rear of engine compartment ...
DO TEST
B : Blower High
Speed Relay Test
E:
AIC Mode
Selector Test
A: Blower Motor Test
E: A!C Mode Selector
Test
C: Blower Resistors
Test (Continued
from previous column)
A: BLWER MOTOR TEST
Measure: VOLTAGE
At: BLOWER MOTOR CONNECTORS
(Disconnected)
Conditions:
Ignition Switch: RUN
Q NC Mode: VENT
Blower Switch:
HI
If your symptom does not appear in the SY~P- (A: BLOWER MOTOR TEST continued on fat- tom Table, perform all of the tests. ing page)
Hi speed only
Blower runs in Lo at
M1 or M2
No Hi speed
operation
B: Blower High
Speed Relay Test
D: Blower Switch
Test
D: Blower Switch
Test
B: Blower High
Speed Relay Test
D: Blower Switch
I Test 1
(Continued in next column)

AIR CONDITIONING: BLOWER CONTROLS
C60, MANUAL
(D: BLOWER SWITCH TEST (TABLE 1) con- (Continued
from previous column) (Continued
from previous column)
tinued on previous page)
D: BEClVVER SWITCH TEST (TABLE 2)
(TAN) '
Ground
D (LT BLU) &
Ground
Between I Voltage I Diagnosis
Battery
Volts
Measure: VOLTAGE
At:
BLIWEW HIGH SPEED RELAY
CONNECTOR
(Disconnected)
, Conditions:
ignition Switch: RUM
A/C Mode: VENT
' @ Blower Switch: M2
See 3 & 6
See 4
Blower Switch: M2
~easure I Correct
E: AIC MODE SELECTOR TEST
At: A/C CONTROL HEAD CONNECTOR
(Connected)
Conditions:
lgnition Switch: RUM
Ground 0
Volts
D (LT BLU) 8
Ground
For
A (ORN) &
ground
Between I Voltage I Diagnosis
If all voltages are correct, go to Table 2.
1. Check YEL (51) wire for an open.
2. If voltage is present, check TAN (63) wire
for a wire to wire short to voltage. If wire
is good, replace the Blower Switch.
3. Check the TAN (63) wire for an open.
4. If voltage is present, check LT BLU (72)
wire for a wire to wire short to voltage.
If
wire is good, replace the Blower Switch.
5. Check Lt BLU (72) wire for an open.
6. If battery voltage is not present at terminals
A,
G or D, go to Test E. If voltage is present
at one or more of the terminals, replace the
Blower Switch.
Battery
e A/c Mode: OFF
I (BRN) & I Battery
Ground I see 1 /
If voltages are correct, Blower Switch is op-
erating normally. Return to Symptom
Table.
1. If voltage is present, check ORN (52) wire
for a wire to wire short to voltage. If wire is
good, replace Blower Switch.
2. Check ORN
(52) wire for an open. If wire is
good, replace Blower Switch.
Battery
See 5
& 6
Measure I Correct
See 2
For
I e AIC Mode: All positions except OFF I
D (BRNNHT)
& Ground
I (BRNIWHT) I Battery & Ground I see 3 /
(Continued in next column)
Volts
@ If all voltages are correct, check the BRNI
WNT (64) wire for an open. If wire is good
replace the Blower Switch.
1. Check BRN (50) wire for an open back to
HTR
A/C Fuse.
2. If voltage is present, check BRNIWNT
(64) wire for a wire to wire short to volt-
age. If wire is good, replace
A/C Control
Head.
3. If battery voltage is present at terminal E
but is not present at terminal D, replace
the
AIC Control Head.
See 2 The
Blower Motor speed is controlled by the
Blower Switch in the
AIC Control Head. With the
switch in the LO position, all of the Blower Re-
sistors are in the circuit with the motor so that it
runs slowly. In the
M1 and M2 positions, the
Blower Switch bypasses some of the Resistors, in-
creasing the Motor speed.
Voltage is applied to the Blower Motor
through the contacts of the Blower Nigh Speed
Relay. When the Blower Switch is in the
HI
position, battery voltage is supplied through
the ORN wire to the coil of the Blower High
Speed Relay. The Relay is energized and its
contacts supply battery voltage directly to the
Blower Motor from Fusible
Link B.
When the Mode Selector is in the OFF posi-
tion, no voltage is applied to the Blower Switch
and Motor so the Blower does not run. In all
other positions, the Blower will operate as
described.
(Continued in next column)

AIR CONDITIONING: COMPRESSOR CONTROLS OD D
C60. MANUAL I I
(Continued from previous page) COMPONENT LOCATION
.......................... $177. Engine harness,
top RN front of engine ........ 201- 5-A
.......................... $204. I/P harness, behind instrument cluster. ........ 201-10-A
SYSTEM CHECK TABLE
I ACTION I EXPECTED RESULT I
1. Turn the Ignition Switch to RUN and start the engine A click can be heard when the clutch engages
Move the
A/C Mode Selector to OFF then to MAX
2. Move the Mode Selector between OFF and MAX several times Verify
that the clutch engages in the MAX position
I I Clutch plate movement can be seen on the front of the comgressor pdey I
I I If the clutch does not engage, proceed to step 4
If the clutch operates as expected, continue to step
3
3.
Put the Mode Selector in MAX to engage clutch Check
that air from the coolant fan can move freely through condensor
1 1 Feel the input (cool) and output (warm) pipes to the cornpressor I
I
If there is not a wide temperature difference after the compressor has run
for several seconds, see Section 1B for refrigerant and compressor diag-
nostics
4. Turn off the ignition If the
refrigerant charge is low, follow the procedures in Section 1B for
Check the refrigerant charge, according to the procedures in Section
1B refrigerant diagnosis
If the refrigerant charge is normal, isolate the conations using the pro-
cedures which follow in the System Diagnosis