Chevrolet 1977 light duty truck Service Manual page 35

B L O W E R M O T O R IN O P E R A T IV E
( A N Y
Check fuse
in fuse pane!.
I_ J L _
FU S E B L O W N
" I___ I
W ith I g n itio n s w itc h in
" R U N " p o s itio n and b lo w e r
speed s w itc h " O N " use
m e te r to lo c a te s h o rt in one
o f th e fo llo w in g w ire s :
1. F ro m fuse p an el to b lo w e r
speed s w itc h .
x
2. F ro m b lo w e r speed s w itc h
to h eater re sisto r.
P O O R O R NO G R O U N D
3. F ro m h e a ter re s is to r to
b lo w e r.
R e p a ir g ro u n d
N o te : S h o rt c ir c u it m a y be
in t e r m it t e n t . I f m e te r does
n o t in d ic a te a s h o rt c ir c u it,
m o ve harness a ro u n d as
| L A M P L IG H T S
m u c h as p o s sib le to re-create
X
s h o rt c ir c u it . W a tc h and
Replace Motor
lis te n f o r a rc in g .
L A M P D O E S N O T L IG H T
Use 12 v o lt te s t lig h t a nd c h e c k feed
te r m in a l (b ro w n ) o n b lo w e r speed s w itc h .
L A M P D O E S N O T L IG H T
R e p a ir o p e n in b ro w n w ire
f r o m b lo w e r speed s w itc h
to fuse pan el.
HEATER C IRC U IT DIA GN O SIS*
SP E E D)
X
FU S E O K
T h e fo llo w in g te sts s h o u ld be m ade w it h
th e ig n itio n s w itc h in " R U N " p o s itio n
th e b lo w e r speed s w itc h " O N " a n d th e
lever on h e a t p o s itio n .
X
Check b lo w e r m o to r g ro u n d
X
G R O U N D O K
x
Check m o to r c o n n e c to r
w it h 12 v o lt te s t lig h t.
X
L A M P D O E S N O T L IG H T
Check blower feed wire in connector
on resistor with 12 volt test light
| L A M P L I G T T )
h
Repair open in feed wire
from resistor to blower motor.
L A M P L IG H T S
Replace switch
"See heater circuit diagrams