Chevrolet 10 Series 1970 Service Manual page 637

CRUISE POSITION
BUTTON RELEASED'
ENGAGE POSITION
BUTTON PARTIALLY
DEPRESSED
TRIM POSITION
BUTTON FULLY
DEPRESSED
BROWN
BLUE
BLACK
ENGAGE SWITCH
CONFIGURATION
BROWN/WHITE STRIPE
(brown w ire ) and term in a l #3 (black). No continuity
shall be shown; how ever, when the button is d e­
p re s s e d halfway, continuity shall be indicated. When
the button is p res sed a ll the way down, no continuity
shall be shown.
T e s t #3 - Connect ohm m eter between term in al #2
(blue w ire ) and term in al #3 (black). Button relea sed ,
no continuity; h ow ever, when the button is depressed
p a rtia lly and fu lly, continuity shall be shown.
4. Disconnect engage switch w ire
fro m the main harness connector (re , brown/white,
and white w ire s ). Connect ohm m eter between point
C (brown/white strip e w ire in main w ire harness)
and ground. Make sure
grounded to the chassis. The ohm m eter should read
between 42 and 49 ohms. I f a resistan ce eith er above
o r below the value indicated is shown, then discon­
nect the connector fro m the regu lator and m easure
the resistan ce o f the brown/white strip e w ire from
point C to D. It should m easure 40 ohms
I f a resistan ce eith er above o r below the value in­
dicated is shown, the main w irin g harness should be
rep laced. Note: When disconnecting o r reconnecting
the main w irin g harness connector fro m the regu la ­
to r, ca re should be e x e rc is e d so as not to damage
the blade connectors o r the w irin g harness.
disconnect m ay be fa cilita ted by p ryin g ca refu lly
on the p la stic connector with a sm all blade screw
d riv e r.
When m easuring the solenoid c o il circu it r e s is ­
tance between Poin t E (Hold T e rm in a l) to ground the
id eal ohm ic resistan ce
ohms. A reading o f le s s than 4 ohms indicates short­
TO " ACC FUSED"
TERMINAL OF
FUSE PANEL
WHITE
REGULATOR
CONNECTOR
F ig . 9 —C ruise M a s te r W irin g D iagram
harness connector
t h e regu lator is w e ll
2 ohms.
The
should be between 5 and 6
REGULATOR
ing in the c o il circu it. A reading o f m ore than 7 ohms
indicates e x c e s s iv e resista n ce in the co il circu it. E ith er
ex trem ity indicates replacem ent of the regu lator assem ­
bly. The white main harness w irin g fro m Point F to G
should also be checked fo r continuity.
ENGAGEM ENT SWITCH TEST
B U T T O N PO SITIO N
C ruise (relea sed )
Engage (p a rtia lly dep ressed )
T r im (fully depressed)
SERVO A N D V A C U U M CHECK OUT
T o determ ine the condition o f the diaphragm , rem ove
hose fro m s e rv o unit and apply 14 inches o f vacuum to the
tube opening and hold in fo r one minute. The vacuum
shall not leak down m ore than 5 inches o f vacuum in one
minute. If leakage is detected, replace servo. T o u tilize
engine as a vacuum sou rce, proceed as follow s:
1. DISCONNECT SERVO BEAD CH AIN and hose from
se rv o then connect engine vacuum d ir e c tly to the
s e rv o fitting.
2. Note position o f s e rv o diaphragm.
3. Start engine - the diaphragm should pull in.
4. Clamp o ff engine vacuum supply line and check fo r
leakage.
The cru ise re le a s e brake switch (vacuum) and con­
necting hoses can lik ew ise be checked using a vacuum
pump.
ACCESSORIES 15-7
CLUTCH
SWITCH
I ' ' BROWN/
WHITE
STRIPE
T E R M IN A L S
1 TO 2 1 TO 3 2 TO 3
closed open
open
closed closed closed
open open
closed
CHEVROLET TRUCK SERVICE MANUAL