Chevrolet 1977 light duty truck, Service Manual

Page: 44 / 861

I N S T A L L V A L V E W I T H A R R O W
P O I N T I N G A W A Y F R O M TEE.
O R I E N T V A L V E S O " O N " " O F F ”
IS VISIBLE
Fig. 1 A -18-W ater Valve In s ta lla tio n - G Model Shown Fig. 1 A 1 9--A uxiliary Heater Control
as Typical
Hi------------ 1
n MEDl
U
i D L O
|BAT_____
BLOWER
SW ITCH
n
■
j
,500 ^ ,2BI,N
CIRCUIT
OFF B A T -O N L Y
LO BAT -LO
MED BAT -M ED
HI BA T -H I
HEATER O PE RATIO N
LO
BAT-BLO SW-RES Rl R2-
BLO M TR-G RD
MED
BAT-BLO SW-RES R2 -
BLO M TR-G RD
HI
BAT -BLO SW -
BLO M TR-G RD
- 1 4 O R N -
-1 4 YEL-
- 1 4 LBL-
12 BRN
5 0 C
5 0 A
I
15 A M P
INLINE FUSE
16 BRN{
s
OB]
"C K " I G N # 3 - 3 0 0 UNFUSED
" G " IG N A C C # 4 FUSED
FUSE
PANEL
v/\ZV\Arf
Rl
v W i
R2
b l c l
L
I
m e d l o
" I
51
5
5 2 A
2B
14 OR N
|52B|
[ 5 2 ]
14 B
BLOWER
RESISTOR
M H 1
GRD (o
BLOWER
M O T O R
Fig. 1A -20-E lectrical Diagram - All Models
ON VEHICLE SERVICE
Since a detailed list o f installation instructions is
included with the auxiliary h e a te r unit, replacem ent
procedures will not be repeated in this section.
CAUTION: G M odels--W hen replacing heater
hoses, m aintain a 1 /2 " m inim um clearance
between hose clip a n d upper control arm , a