PONTIAC FIERO 1988 Service Repair Manual

DEFOGGER I:
SEE FUSE BLOCK
DETAILS
DEFOGGER
CONTROL
DISTRIBUTION
-

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: ALL SYSTEMS OD P
SYSTEM CHECK
Use the System Check Table as a guide to
normal operation.
All of the checks can be
pedormed without the use of tools or dis-
assembly of components.
Even though one or
more checks may not give
a normal result, complete the entire System
Check to reveal ail symptoms which may
exist.
SYSTEM CHECK TABLE
(SYSTEM CHECK TABLE continued on facing page)

AIR CONDITIONING: ALL SYSTEMS
(SYSTEM CHECK TABLE continued from facing page)
Set Temperature lever to COLD
13. OFF
If all of the above steps can be completed as described, the Air Conditioning and I-leating system is operating normally.
Blower and Compressor turn off 8A-63,64 Blower and Compressor Controls
8A-66,67 Blower and Compressor Controls

3 AIR CONDIB18NING: BLOWER CONTROLS
C60, MANUAL
POWER DISTRIBUTION
1 ORN
BLOWER
RESISTORS