PONTIAC FIERO 1988 Service Repair Manual

INTERIOR LIGHTS DIMMING
(Continued from previous page)
WITHOUT DIGITAL CLUSTER
A: llUTERlOR LIGHTS DlMMlNG TEST
Connect: TEST LAMP
At: FUSE BLOCK-HOT
SIDE OF lNST LP FUSE
Conditions:
e ignition Switch: RUN
lNST LP Fuse: REMOVED
Light Switch: PARK
Dimmer Control: BRIGHT
Connect Correct
For
Between Result Diagnosis
INST LP Fuse Test Lamp cavity (DK See 1
GRN) & lights
Ground
I I @ Slowly turn Dimmer Control to DIM I
INST LP Fuse Test Lamp
cavity (DK See 1
1 GRN) & 1 dims 1 1
I Ground I I 1
If all results are correct but Interior Lights
do not work, check the GRY
(8) wire for an
I open (see schematic). I
1. Check DK GRN (44) wire for an open. If
I wire is good. do %st B.
B: REMOTE DIMMER TEST
At: REMOTE DIMMER CONNECTOR
1. Check BRN (9) wire for an open (see
2. Check DK GRNIWNT (844) wire for an
open (see schematic). If wire is good, do
C: LIGHT SWITCH TEST
Connect: TEST LAMP
At: LIGHT
SWITCH CONNECTOR 62
(Connected)
Conditions:
r Light Switch: PARK
a Dimmer Control: BRIGHT
Connect Correct For
Betvveen Result Diagnosis
(BRN) Test
Lamp
, &Ground lights See 1
1
A I I Test Lamp
lights I See 2 /
I Ground I I I
I Slowly turn Dimmer Contml to DIM I
dims
Ground
If all results are correct but Interior Lights
do not dim, check the DK
GRNIWNT (844)
wire for an open.
1. Check the BRN (9) wire for an open.
2. Repairlreplace the Light Switch.
CIRCUIT OPERATION
Voltage is applied at all times to the Light
Switch through the Tail Fuse. With the Light
Switch in
HEAD or PARK, voltage is applied
through the Light Switch, Remote Dimmer, and
INST LP Fuse to the various Instrument Panel
and Console Lights. The lights can be dimmed
using the rheostat in the Light Switch.

POWER WINDOWS
--- ------ *DO 1 FUSE LOCK CmT I- ! I {- BREAKER !
WOO 35AMP I L,-2 ,----- -I
3 PNK 76 1

POWER WINDOWS
TROUBLESHOOTING HINTS
s Try the following checks before doing the Sys-
tem Check.
1. If no windows operate, check the WDO Cir-
cuit Breaker by visual inspection.
2. If no windows operate, check that ground
6309 is clean and tight.
e Go to System Check for a guide to normal
operation.
e Go to System Diagnosis for diagnostic tests.
COMPONENT LOCNIOM Page-Figure
..................... ...... Fuse Block. Behind LH side
of IIP, below light switch. 201-10-A
................. ............. VVindow Motors In lower front corner of each door 201-18-A
................ ........ C238 (12 cavities) LH shroud, ahead of center access hole. 201-11-C
.......................... 6309 Below rear of console
.......................... S301. Crosscar harness, below LR front seat
SYSTEM DIAGNOSIS A: LH FRONT POWER WINDOW
e Do the tests listed for your symptom in the SWITCH TEST
Symptom Table below.
e Tests follow the Symptom Table.
SYSTEM CHECK SYMPTOM TABLE
* Use the System Check Table as a guide to
normal operation.
Refer to System Diagnosis for a list of symp-
toms and diagnostic steps.
SYSTEM CHECK TABLE
and DN from the
moothly, with no
EH Front Power
Window Switch
RH Front Window
RH Front Power
r Refer to System Diagnosis when a result
is not normal.
to splice S301 for an
open. If wire is OK,
perform tests A and
RH Front Power
Window does not Window Switch
CONNECTOR (Connected)
(A: LN FRONT POWER WINDOW
SWITCH TEST continued on next page)

POWER WlNDOWS
(A: LH FRONT POWER WINDOW
SWITCH TEST continued from previous
.page) 6: WINDOW MOTOR TEST
. Check BLK (150) wire for an open (see
B: RH FRONT POWER WINDOW
SWITCH TEST
At: RM FRONT POWER WINDOW SWITCH
CONNECTOR (Connected)
I 0 lanition Switch: RUN I
s Ignition Switch: RUN
Operate associated Power Window
D (PNK) Test Lamp
& B (BLK) Lights See 2
0 Operate
RH Front Power Window
Switch UP and DN
C (LT BLU) ( Test Lamp ( See & A (TAN) lights
0 If all the results are correct, go to Test C.
1. Check PNK (76) wire for an open (see sche-
matic).
2. Check BLK (150) wires for an open (see
schematic).
3. Replace RN Front Power Window
Switch. With
the Ignition Switch in RUN, voltage is
applied through the
WDO Circuit Breaker and
the PNK and
PNKIWNT wires to the Power
Window Switches. With the LH Front Power
Window Switch in UP, voltage is applied
through the WDO Circuit Breaker, the
LN
Front Power Window Switch, and the DK BLU
wire to the LH Front Window Motor. The
Motor is grounded through the BRN wire and
the DN contacts of the LN Front Window
Switch to 6309. The motor runs and the
window goes up. Voltage is
similarly applied
with the RN Front Power Window Switch in
UP.
In DN, voltage is applied to each motor in the
opposite direction and the window goes down.

x POWER DOOR LOCKS I $
DEFOGGER

POWER DOOR LOCKS
TROUBLESHOOTING HINTS
Try the following checks before doing the
Systern Check.
1. Check the PWR ACC Circuit Breaker by
operating the Defogger.
2. Check the CTSY Fuse by operating the
Horn.
3. Check that the Door Lock Relay Assembly
case ground is making good contact.
4. If one or more of the door lock motors do
not operate properly, but the other door
locks function normally, check the wiring to
the motors. If the wiring is correct, replace
that motor.
s Go to System Check for a guide to normal
operation.
Go to System Diagnosis for diagnostic tests.
SYSTEM CHECK
Use the System Check Table as a guide to
normal operation.
r Refer to System Diagnosis for a list of symp-
toms and diagnostic steps.
SYSTEM CHECK TABLE
COMPONENT LOCATION Page-Rgure
Door Lock Motors. ............... In each door, near lower rear corner ........... 201-18-A
Door Lock Relay Assembly
........ LN shroud, near lower access hole ............ 201-11-B
Fuse Block. ..................... Behind LH side of IIP, below light switch. ...... 201-10-A '
C238 (12 cavities) ................ LH shroud, ahead of center access hole. ........ 201-11-C
S203. .......................... IIP harness, behind instrument cluster. ........ 201-10-A
S233. .......................... IIP harness, above Fuse Block. ............... 201-10-A
(Continued from previous column)
Door Lock Switch
to the LOCK
position, close the SYSTEM DIAGNOSIS
r Do the tests listed for your symptom in the
Symptom Table below.
Tests
follow the Symptom Table.
SYMPTOM TABLE
Test on suspect
Door Lock Motor
The Power Door
B: Door Lock Switch
Locks do not Test on suspect
operate from one Door Lock Switch
Door Lock Switch
The Power Door
C: Door Lock Relay
Locks do not
I Test
r Refer to System Diagnosis when a result is operate from any B: Door Lock Switch
not normal. Door
Lock Switch Test
(Continued in next column)
(Continued on next page)

POWER DOOR LOCKS
IT
(Continued from previous page)
A: DOOR LOCK MOTOR TEST
At: SUSPECT DOOR LOCK MOTOR
CONNECTOR (Disconnected)
suspect Door Lock Motor.
1. Check the TAN (294) wire for an open
(see schematic).
2. Check the GRY (295) wire for an open
B: DOOR LOCK SWITCH TEST
(Continued from previous column)
See 2
If
all the voltages are correct, check the
LT BLU (195) wire and BLK (194) wires
for an open (see schematic).
1. Check the CTSU Fuse. Check the ORN
6: DOOR LOCK RELAY TEST [TABLE '11
Connect: TEST LAMP
At: DOOR LOCK RELAY CONNECTOR
61 (Disconnected)
A (ORN' Test Lamp
BLK) & See 1
1 Ground 1 lights
If the result is correct, proceed to Table 2.
1. Check the PWRIACC Circuit Breaker and
the
ORNIBLK (60) wire for an open (see
schematic).
(Continued in next column)
6: DOOR LOCK RELAY TEST (TABLE 2)
Connect: TEST LAMP
At: DOOR LOCK RELAY CONNECTORS
C1 & 62 (Connected)
Condition: Door Lock Switch: LOCK and hold
Move the Door Lock Switch to UN-
I LOCK and hold
C1: C (GRY)
Test See
3
(Continued on facing page)

POWER DOOR LOCKS
(Continued from previous facing page)
TAN (294) and GRY (295) wires for
opens (see schematic). If the wires are
OK, do Test A.
1. Check the LT BLU (195) wire for an open
(see schematic). If the
wire is good, do Test
2. Check the BLK (194) wire for an open
(see schematic). If the wire is good, do
CIRCUIT OPERATION
When a Door Lock Switch is activated in
the Power Door Lock system, all of the doors
will lock or unlock in unison. Each lock can
also be operated manually from the locking
post. The locks are operated by reversible
Motors that receive voltage from two relays in
the Door Lock Relay Assembly. These relays
operate to turn the Motors on by applying a
voltage to one of the terminals and a ground to
the other terminal.
When either Door Lock Switch is moved to
the LOCK position, it completes the circuit to
the coil of the Door Lock Relay Assembly. The
lock relay is energized. The contact for the
Lock Relay closes, and is connected to battery
voltage through the
ORNIBLK wire which is
the high current feed for driving the Motors. Voltage
is then applied to the GRY wire and
the Door Lock Motors, which are grounded by
the TAN wire from the other terminal of the
Motor through the contact for the Unlock Re-
lay. The Motor in each door runs to operate the
Door Locks. When the Door Lock Switch is
released, the Lock Relay contact returns to
ground and the Motors turn off.
A similar action occurs with the unlock relay
when it is energized by either of the Door Lock
Switches closing to the UNLOCK position.
Now the TAN wires to the Motors carry bat-
tery voltage and the GRY wires are grounded.
The polarity of the voltage to the Motors has
been reversed. The Motors run in the opposite
direction to unlock the doors.
The Door Lock Switches are usually closed
for just a moment. If they are held closed, a
circuit breaker in each motor will open to pro-
tect against damage. The circuit breakers close
automatically when they cool off.