1988 PONTIAC FIERO Service Repair Manual

HORNS I $
FUSE - BLOCK -
CONVENIENCE CENTER

HORNS
TROUBEESHOOTlNG HINTS
Try the following checks before doing the
System Diagnosis.
1. If the Horns do not sound at all, check the
CTSY Fuse by operating the Cigar Lighter.
2. If only one Worn sounds, check the DK GRN
(29) wire and the suspect Horn.
Go to System Diagnosis for diagnostic tests.
SYSTEM DIAGNOSIS
Diagnostic steps for the symptoms listed in
the following table are listed after the table.
SYMPTOM TABLE
A: The Horns sound continuously
B: None of the Horns sound
A: THE HORNS SOUND
GONTlNUOUSLY
COMPONENT LOCATION Page-Figure
.............. Convenience Center Behind IIP, to
right of steering column. ........ 201-10-A
..................... ...... Fuse Block. Behind LH side
of I/P, belour light switch. 201-10-A
.................... Horn Switch Below
steering wheel hub
....................... Slip Ring Below
steering wheel hub
................ el00 (42 cavities) LH front of dash, left of brake master cylinder .. 201- 0-A
................ C210 (11 cavities) Behind IIP, on
RW lower side of steering column. 201- 9-A
.......................... S203. IIP harness, behind instrument cluster. ........ 201-10-8
B: NONE OF THE MORNS SOUND
(TABLE a,
Connect: TEST LAMB
IiENcE CENTER
I Condition:
a Horn Relay disconnected
Connect
Between I ","d::r I For Diagnosis
A (ORN) &
Ground
B: NOME OF THE HORNS SOUND
(TABLE 21
Horn Switch: ON
Jumper
Between
Test
Lamp lights
(Continued on next page)
See 1
See 2 A (ORN) &
B (BLK)
If all the results
are correct, go to Table 2.
1. Cheek the ORN (40) wire for an open (see
schematic).
2. Check the BLK (28) wire and the Horn
Switch for an open (see schematic).
Test
Lmp lights

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.