1988 PONTIAC FIERO Service Repair Manual

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

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 I z
660, MANUAL
(A: BLOWER MOTOR TEST continued from
facing page)
I Measure I Correct For
Between
I Voltage I Diagnosis
I (PPL) & 1 Battery I See 1 ( Ground
1 (yi,"g C2 I Battery 1 see 2 1
e If the voltages are correct but the blower
does not run, install a new Blower Motor.
1. Check the PPL
(65) wire for an open. If the
wire is good, go to Test B and Test D.
2. Check the BLK (150) wire for an open and
that ground
6112 is clean and tight (see
schematic).
B: BLOWER HIGH SPEED RELAY TEST
(TABLE
1)
(Continued from previous column)
Measure: VOLTAGE
At: BLOWER RELAV CONNECTOR
(Disconneded)
Conditions:
@ lgnition Switch: RUN
e AlC Mode: VENT
r Blovver Svvitch: HI
@ If all voltages are correct, go to Table 2.
1. Check RED (2) wire for an open back to
Fusible Link B.
2. Check ORN (52) wire for an open. If wire is
good, go to Test D.
3. Check PPL (65) wire for an open between
the Blower Nigh Speed Relay Terminal B
and the Blower Resistors Terminal B. If
wire is good, go to Test C.
Measure
Bemeen
(RED) &
Ground
A (ORN) &
Ground
B: BLClVVER HIGH SPEED RELAY TEST
(TABLE
2)
Measure: RESISTANCE
At:
BLClWER HIGH SPEED RELAY
CONNECTOR
(Disconnected)
Conditions:
lgnition Switch: OFF
Negative Battery Terminal:
DISCONNECTED
Correct
Voltage
Battery
Battery
I 'g;dd& I o ohms I see I I
~easure I Correct
Between
For
Diagnosis
See 1
See 2
Blower Switch: LO
B (PPL) & Less than 3
Ground See
2
For
B (PPL) &
Ground
a If all results in Table 1 and Table 2 are
correct, but Blower Relay does not oper-
ate or Blower runs
all the time, replace the
Blower Relay.
1. Check the BLK (150) wire for an open.
2. Check the PPL (65) wire for an open. If wire
is good, go to Test A.
I I Resistance
6: BLOWER RESlSTORS TEST
Diagnosis
Battery
See 3
D: BLOWER SWITCH TEST (TABLE 1)
Measure: VOLTAGE
At:
BLOVVER RESISTORS CONNECTOR
(Disconnected)
Conditions:
r lgnition Switch: RUN
AlC Mode: VENT
Blower Switch: LO
Measure:
RESISTANCE
At: BLOWER RESISTORS
(Disconnected)
Condition: lgnition Switch: OFF
I Measure I Correct I For I
Between 1 Voltage I Diagnosis For
Diagnosis
See 1
See 1
Measure
Between
A&C
C&D
I A (YEL) & 1 Battery I See 1 & 6 / Ground
0.7 rt 5 ohm
If the results are correct, Blower Resistors
are operating normally. Return to Symptom
Table.
1. Install new Blower Resistors.
Correct
Result
1.5 rt 1 ohm
0.2rt1 ohm
( @ Blower Switch: M1 I
C (TAN) &
Ground
(D: BLOWER SWITCH TEST (TABLE 1)
continued on next page)
(Continued in next column)
I&
0 Volts See 2