Pontiac Fiero 1988 Service Manual page 36

HEATING AND VENTILATION 1A-11
6 > BLOWER NOISE
C H E C K ALL E L E C T R I C A L CONNECTIONS AND GROUNDS FOR P R O P E R CONNECTIONS. IF IN
DOUBT, U S E A VOLTMETER TO C H E C K FOR CONSTANT VOLTAGE AT THE BLOWER MOTOR.
SIT IN T H E V E H I C L E WITH T H E D O O R S AND WINDOWS C L O S E D . WITH THE IGNITION ON
AND T H E ENGINE OFF, START WITH T H E BLOWER ON HIGH, IN VENT MODE AND THE
T E M P E R A T U R E L E V E R ON F U L L C O L D . C Y C L E T H R O U G H BLOWER S P E E D S , MODES AND
T E M P E R A T U R E DOOR POSITIONS TO FIND W H E R E THE NOISE O C C U R S AND W H E R E THE
NOISE D O E S NOT O C C U R . T R Y TO DEFINE T H E T Y P E O F NOISE: AIR RUSH, WHINE,
TICK/CLICK, S Q U E A L / S C R E E C H , F L U T T E R , RUMBLE OR SCRAPING NOISE. CHART
BELOW SHOULD B E C O M P L E T E L Y FILLED IN AT COMPLETION.
A CONSTANT AIR RUSH NOISE IS TYPICAL O F ALL S Y S T E M S ON HIGH BLOWER. SOME
S Y S T E M S AND MODES (USUALLY D E F R O S T E R ) MAY B E W O R S E THAN O T H E R S . C H E C K
ANOTHER V E H I C L E IF P O S S I B L E (SAME MODEL) TO DETERMINE IF THE NOISE IS
TYPICAL O F T H E S Y S T E M AS DESIGNED.
INDICATE T H E T Y P E O F NOISE AND W H E R E IT O C C U R S :
VENT
HEATER D E F R O S T !
F U L L
COLD
F U L L
HOT
F U L L
COLD
F U L L
HOT
F U L L
C O L D
FULL
HOT
LOW
BLOWER
M2
M3
HIGH
BLOWER
A—WHINE, B—CLICK/TICK, C — S Q U E A L / S C R E E C H , D — F L U T T E R , E -
F — S C R A P I N G , G—AIR R U S H , H—OTHER, D E S C R I B E
-RUMBLE,
1. NOISE IS CONSTANT
BUT L E S S E N S WITH
BLOWER S P E E D R E D U C -
TION. TYPICAL N O I S E S
A R E WHINE, TICK/CLICK
F L U T T E R OR
SCRAPING NOISE.
2. NOISE IS AT START-UP
ONLY OR IS INTERMITTANT.
MAY O C C U R AT C O L D AM-
BIENTS AND LOW BLOWER
S P E E D S . TYPICAL NOISE
IS AN O B J E C T I O N A B L E
S Q U E A L / S C R E E C H .
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3. NOISE IS CONSTANT AT HIGH
BLOWER S P E E D S WITH SOME
DOOR COMBINATIONS BUT CAN
B E ELIMINATED AT LOWER
BLOWER S P E E D S OR WITH
OTHER DOOR COMBINATIONS.
TYPICAL NOISES A R E
F L U T T E R OR RUMBLE
CONTINUED AT TOP OF NEXT PAGE
G20009-1 A
Figure 12 Blower Noise Diagnosis (1 of 2)