PONTIAC FIERO 1988 Service Repair Manual

HORNS --
(Continued from previous page)
B: NONE OF THE HORNS SOUND
(TABLE
3)
t: HORN CONNECTORS (Disconnected)
. Check DK GRN (29) wire for an open (see
GlRCUlT OPERATION
Voltage is applied to the Horn Relay at all
times. When the Horn Switch is depressed, the
relay coil is grounded and the relay contacts
close. Voltage is then applied to both Horns.
The Horns sound.

BRAKE WARNING SYSTEM
INSTRUMENT CLUSTER
PRINTED CIRCUIT
.5 TANAIVHT
BRAICE FLUID
LEVEL SWITCH
LOW BRAKE FLUID
RELEASE
RELAY

BRAKE VVARNlNG SYSTEM
TROUBLESHOOTING HINTS
0 Try the following checks before doing the
System Diagnosis.
Check the GAGES Fuse and PNKIBLK
(39) wire by observing the VOLTS or
SERVICE ENGINE SOON Indicator with
the Ignition Switch in RUN and the engine
OFF.
0 Go to System Check for a guide to normal
operation.
0 Go to System Diagnosis for diagnostic tests.
SYSTEM CHECK
Use the System Check Table as a guide to
normal operation.
e Refer to System Diagnosis for a list of symp-
toms and diagnostic steps.
SYSTEM CHECK TABLE
RUN position to
BULB TEST
COMPONENT LOCATION Page-Figure
.................. Brake Fluid Level Switch. ......... Below brake fluid reservoir 201-16-A
..................... Fuse Block. Behind
LH side of IIP, below light switch. ...... 201-10-A
................. Ignition Switch. Behind IIP, on
top side of steering column ...... 201- 9-A
Parking Brake Switch.
............ In console, at base of parking brake ........... 201-12-D
................... Release Relay Taped
to IIP harness, behind RH side of IIP. .... 201-13-A
................ (2100 (42 cavities) LR
front of dash, left of brake master cylinder .. 201- 0-A
........................... S204. IIP harness, behind instrument cluster. ........ 201-10-A
.......................... ............... S228. IIP harness, above Fuse Block. 201-10-A
SYSTEM DIAGNOSIS
0 Diagnostic steps for the symptorns listed'in
the following table are listed after the table.
A: BRAKE INDICATOR REMAINS ON
WITH THE
IGNITION SWITCH IN
RUN AND THE PARK BRAKE OFF
(TABLE
1)
SYMPTOM TABLE
A BRAKE Indicator remains on with the
Ignition Switch
in RUN and the park
brake off
B BRAKE Indicator lights with the park
brake applied, but does not light when
brake fluid level is low
C BRAKE Indicator does not light at all
D BRAKE Indicator lights with the Igni-
tion Switch in BULB TEST, but does not
light when the park brake is applied
E BRAKE Indicator lights with the park
brake applied, but does not light when
the Ignition Switch is in BULB TEST
Refer to System Diagnosis when a result is
not normal. Disconnect:
CONNECTOR
At: BRAKE FLUID LEVEL SWITCH
Conditions:
0 Ignition Switch: RUN
0 Park Brake: OFF
Pressure Warning
If the result is correct, refer to Section
5 to
test the Brake Hydraulic System.
Replace the Brake Fluid Level Switch if
the Brake Hydraulic System is OK.
1. Go to Table2.

BRAKE WARNING SYSTEM I:
A: BRAKE INDICATOR REMAlNS ON
WITH THE lGNlTlON SWITCH IN
RUN AND THE PARK BRAKE OFF
(TABLE
2)
Disconnect: CONNECTOR I
At: PARKING BRAKE SWITCH
Conditions:
0 lgnition Switch: RUN
0 Park Brake: OFF
Disconnect
I Correct Result I For Diagnosis
Parking Brake
connector not light
If the result is correct, checklreplace the
Parking Brake Switch
1. Check the Ignition Switch for a short to
ground in the RUN position. If Ignition
Switch is good, check TANIWHT
(33)
wires for a short to mound.
B: BRAKE INDICATOR LIGHTS WITH 6: BRAKE INDICATOR DOES NOT
THE PARK BRAKE APPLIED, BUT
LIGHT AT ALL
DOES NOT
LIGHT WHEN BRAKE
FLUID LEVEL IS LOW
1. Check Indicator bulb, TANIWHT (33)
Connect: FUSED JUMPER
At: BRAKE FLUID LEVEL SWITCH
CONNECTOR
Conditions:
lgnition Switch: RUN
0 Park Brake: OFF
Connect
Between
Brake Fluid
Level Switch
Connector
&
Ground
If the result is correct, checklreplace the
Brake Fluid Level Switch.
1. Check TANIWHT (33) wire for an open.
Correct Result
Brake
Warning
Indicator lights
For Diagnosis
See 1

BRAKE WARNING SYSTEM
H CONNECTOR
epair TAN/WHT (33) wire for
D: BRAKE INDICATOR LIGHTS WITH E: BRAKE INDICATOR LlGHTS WITH
THE IGNITION SWITCH IN BULB THE
PARK BRAKE APPLIED, BUT
TEST, BUT DOES NOT
LIGHT WHEN DOES
NOT LIGHT WHEN THE
THE PARK BRAKE IS
APPLIED IGNITION SWITCH IS IN BULB TEST
At: IGNITION SWITCH CONNECTOR 61
If the result is correct, check/replace
the Ignition Switch.
1. Checklrepair TAN/WHT (33) wire for
ClRCUlT OPERATION
Battery voltage is applied to the BRAKE
Warning Indicator when the Ignition Switch is
in RUN, BULB TEST, or START. Three
switches are connected to the BRAKE Warn-
ing Indicator. When any one of these switches
closes, ground is provided and the Indicator
lights.
The Ignition Switch provides a ground when
it is in the BULB TEST and START posi-
tions. The BRAKE Warning Indicator lights.
The Parking Brake Switch provides a
ground when the park brake is applied. The
BRAKE Warning Indicator lights to alert the
driver.
The Brake Fluid Level Switch closes to light
the
BRAKE Warning Indicator when there is
low brake fluid in one of the two hydraulic brake
systems. This could be caused by a leak in one of
the brake lines. The switch can be reset to
an
open condition by refilling the reservoir. This
can only be accomplished after the faulty sys-
tem has been repaired.

HEATER

HEATER
TROUBLESMOOTlNG HINTS
e Try the following checlcs before doing the
System Check.
1. If the Blower Motor does not operate at all,
check the
HTR A/C Fuse.
2. If the Blower Motor does not operate at all,
check that
GI08 is clean and tight.
3. If the Blower Motor does not turn off, in-
stall
a new Blower Switch.
r Go to System Check for a guide to normal
operation.
r Go to System Diagnosis for diagnostic tests.
SYSTEM CHECK
Use the System Check Table as a guide to
normal operation.
e Refer to System Diagnosis for a list of symp-
toms and diagnostic steps.
SYSTEM CHECK TABLE
ACTION 1 NORMALRESUU 1
COMPONENT LOCATION Page-Figure
Blower Motor (Without
AlC) ....... RH front of dash, behind strut tower .......... 201-14-D
Blower Resistors (Without AIC) .... RH front side of heater housing .............. 201-14-D
Fuse Block.
..................... Behind LH side of IIP, below light switch. ...... 201-10-8
C202 (1 cavity) .................. Behind center of UP, near control head. ........ 201-14-C
GPO8 .......................... RH front of dash, above center of Blower Motor . 201-14-D
SYSTEM DIAGNOSIS
Do the tests listed for your symptom in the
Symptom Table below.
Tests follow the Symptom Table.
SYMPTOM TABLE
A: BLOWER SWITCH TEST
0 If your symptom does not appear in the (A: BLOmR SWITCH TEST continued on Sympton Table perForm all of the Tests. next page)
not normal. Measure:
VOLTAGE
At: BLOWER
SWITCH CONNECTOR
(Connected)
Condition:
a ignition Switch: RUN
Measure Correct For
Between Voltage Diagnosis
P P
See 1
Blower Switch: LO
&
Ground Battery
See 2
* Blower
Switch: MED
(LT BLU)
& Ground
* Blower Switch: HI
Battery
See 2

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).