GMC 1982 Light Duty Truck, Service Manual

Page: 61 / 1435

IB - 18 AIR CONDITIONING
_________ i___________
P o s itio n th e c o n tro ls so th a t th e :
T e m p e ra tu re lever is o n f u ll heat.
S e le cto r o r h e ater le ve r is o n H eater.
Fan s w itc h is o n H i.
| CHECK BY PA S S D O O R OUTLET FOR AIR F L O W |
N O A IR FL O W A IR FL O W
C H E C K D E F R O S T E R O U T L E T S F O R A IR F L O W
( I f in d o u b t as t o H ig h o r L o w a ir f lo w
set s e le c to r o n D E F w h ic h is H ig h and
co m p a re .
Reset se le c to r o n H e ater)
N O O R LO W A IR F L O W
C H E C K H E A T E R O U T L E T A IR F L O W
( I f in d o u b t, s w itc h fan
s w itc h fr o m H i to L o )
[ C H A N G E IN A IR F L O W
N O R M A L A IR F L O W
C heck heater o u tle t te m p e ra tu re
w ith 2 2 0 ° F range th e rm o m e te r.
T
(a p p ro x im a te o u tle t a ir te m p e ra tu re s )
O u tle t A ir 1 4 5 150 155 165
A m b ie n t A ir
0
2 5 4 0 7 5
| N O R M A L T E M P E R A T U R E [
R em o ve a ll o b s tru c tio n s u n d e r fr o n t seat. |
Car does n o t b u ild u p heat - o p e ra te v e n t
c o n tro ls a n d see th a t th e a ir v e n t d o o rs
close c o m p le te ly , if n o t, a d ju st.
LO W T E M P E R A T U R E
n:
(C hec k th e syste m te m p e ra tu re a fte r re ­
p a irin g th e ite m c h e c k e d t o c o m p le te th e
diagnosis.)
I ------
Check c o o la n t level; if lo w , f i l l . L o o k fo r
o r feel a ll ra d ia to r a n d h e ater hoses and
co n n e c tio n s fo r leaks. R epa ir o r repla ce.
C heck th e ra d ia to r cap fo r dam age a n d re­
place if re q u ire d .
C heck h e a te r a n d ra d ia to r hoses fo r k in k s
stra ig h te n a n d repla ce as necessary.
C heck te m p e ra tu re d o o r fo r m a x heat p o ­
s itio n . A d ju s t i f necessary.
| H E A T E R C O R E
Feel te m p e ra tu re s o f h e ater in le t and o u tle t hoses.
W A R M IN L E T A N D O U T L E T H O S E S
C heck e n gine th e rm o s ta t.
A d ju s t b y - p a s s f o r n o a ir f lo w .
| H IG H A IR FL O W
A d ju s t d e fro s te r d o o r fo r lo w a ir flo w .
L IT T L E O R N O C H A N G E IN A IR F L O W
| L O W O R N O A IR F L O W ~ |
LO W A IR FL O W [
C heck he a te r o u tle t fo r o b s tru c tio n - re ­
m ove.
C heck m o to r v o lta g e a t closest m o to r I ine
c o n n e c tio n w ith a v o ltm e te r.
U N D E R 1 0 V O L T S O V E R 10 V O L T S
C heck b a tte ry v o lts - u n d e r 10 v o lts ,
recharge th e n re che ck m o to r vo lta ge.
C heck w irin g a n d c o n n e c tio n s fo r
u n d e r 10 v o lts fr o m m o to r to fan
s w itc h . R epa ir o r repla ce last p o in t
o f u n d e r 10 v o lt re ad ing.
A p p ly e x te rn a l g ro u n d , (ju m p e r w ire ) to
m o to r case. IN C R E A S E D A IR F L O W -
re p a ir g ro u n d .
S A M E A l R F LO W - re m o v e m o to r and
check fo r o b s tru c tio n in syste m o p e n ­
ing. I f no n e , R E P L A C E M O T O R . I f
o b s tru c tio n , re m o v e m a te ria l and re ­
in sta ll m o to r.
C h e c k s h u to ff d o o r p o s itio n fo r fu ll
syste m a ir flo w . A d ju s t if necessary.
N O A IR FLO W
C H E C K FUSE
FU SE B L O W N - re p la ce fuse.
A l R F L O W - syste m o k a y .
B LO W S F U S E
R em ove p o s itiv e lead fr o m m o to r and
repla ce fuse.
FU SE R E M A IN S O K - rem ov e m o to r
and chec k fo r o b s tru c tio n in syste m
o p e n in g , if no n e , R E P L A C E M O T O R .
I f o b s tru c tio n , re m o v e m a te ria l and
re -in s ta ll m o to r.
8 LO W S F U S E - ch e c k fo r sh o rte d
w ire in b lo w e r e le c tric c ir c u it -
See H eater C irc u it D ia g n o s tic C h a rt.
FU S E O K
FU S E O K - See H eater C irc u it
D ia g n o s tic C h a rt.
H O T IN L E T A N D W A R M O U T L E T H O S E S
I ~
C heck p u lle y s , b e lt te n s io n , e tc ., f o r p r o ­
per o p e ra tio n . R eplace o r service as neces­
sary.
I
R em ove hoses fr o m h e ater c o re . Reverse
flu s h w ith ta p w a te r. I f p lug ged, re p a ir o r
replace.