GMC 1982 Light Duty Truck Service Manual page 61

IB -18 AIR CONDITIONING
N O A IR FLO 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 FL O W
( If in d o u b t as to H igh o r L o w a ir flo w
set s e le c to r o n D E F w h ic h is H igh and
com p are. Reset selector o n H eater)
N O O R LO W A IR FL O W
C H E C K H E A T E R O U T L E T A IR FLO W
( I f in d o u b t, s w itch fan
s w itc h fro m H i to Lo)
[ C H A N G E IN A IR FL O W
N O R M A L A IR FLO W
C heck heater o u tle t te m p e ra tu re
w ith 220° F range th e rm o m e te r.
(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
A m b ie n t A ir
| 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 un d e r fr o n t seat. |
Car does n o t b u ild up heat - op e ra te ve n t
c o n tro ls and see th a t th e a ir ve n t d o o rs
close c o m p le te ly , if n o t, ad ju st.
(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 ke d to c o m p le te th e
diagnosis.)
Check c o o la n t level; if lo w , f i ll. L o o k fo r
o r feel all ra d ia to r and heater hoses and
co n n e c tio n s fo r leaks. R epair o r replace.
Check th e ra d ia to r cap fo r dam age a nd re­
place if re q u ire d .
C heck heater a nd ra d ia to r hoses fo r k in k s
stra ig h te n a nd replace as necessary.
C heck te m p e ra tu re d o o r fo r m ax heat po­
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 heater 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 SE S
C heck engine th e rm o s ta t.
H O T IN L E T A N D W A R M O U T L E T H O SE S
C heck p u lle y s , b e lt te n s io n , e tc., f o r p ro ­
per o p e ra tio n . R eplace o r service as neces­
sary.
Rem ove hoses fro m heater c o re . Reverse
flu s h w ith ta p w a te r. I f plugged, re p a ir o r
replace.
_________ i _ __________
P o sitio n th e c o n tro ls so th a t the:
T e m p e ra tu re lever is o n fu ll heat.
S ele ctor o r heater lever is on H eater.
Fan s w itch is o n H i.
| CHECK BY PA S S D O O R OUTLET FOR AIR F L O W |
T
1 45
150 155 165
0
25 40
75
[
LO W T E M P E R A T U R E
n:
I ------
I ~
I
A IR FLO W
A d ju s t b y -p a s s f o r n o a ir flo w .
| H IG H A IR FLO 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 FL O W
| LO W O R N O A IR F L O W ~ |
C heck s h u to ff d o o r p o s itio n fo r fu ll
system a ir flo w . A d ju s t if necessary.
LO W A IR FLO W [
C heck heater 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 10 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 reche ck m o to r volta ge.
C heck w irin g and c o n n e c tio n s fo r
u nde r 10 v o lts fro m m o to r to fan
sw itc h . Repair o r repla ce last p o in t
o f u n d e r 10 v o lt reading.
A p p ly e xte 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 - rem ove m o to r and
check fo r o b s tru c tio n in system o p e n ­
ing. I f none , R E P L A C E M O T O R . If
o b s tru c tio n , rem ove m a te ria l and re­
insta ll m o to r.
N O A IR FLO W
C H E C K FUSE
FUSE B L O W N - repla ce fuse.
A l R F L O W - system o k a y .
B LO W S FU SE
R em ove p o s itiv e lead fro m m o to r and
replace fuse.
FUSE R E M A IN S O K - rem ove m o to r
and check fo r o b s tru c tio n in system
o p e n in g , if none , R E P L A C E M O T O R .
If o b s tru c tio n , re m o v e m ate ria l and
re -in s ta ll m o to r.
8 LO W S FU 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 SE O K
FU SE O K - See H eater C irc u it
D ia g n o stic C h a rt.