Buick LeSabre 1965 Service Manual page 866

ACCESSORIES
ELECTRO-CRUISE 1 1 - 1 3 3
1 1 - 2 4 ELECTRO-CRUISE
TROUBLE
DIAGNOSIS
Whenever a specific complaint is
encountered with the Electro-
Cruise system, the Trouble Diag-
nosis Chart should be used for
reference as to the complaint and
its possible cause. Whenever a
general complaint is encountered,
the Trouble Diagnosis Test Pro-
cedure Chart (figure 11-183)
should be used to determine the
area of malfunction. Since the
procedures outlined in this chart
are performed with the car sta-
tionary, it may be necessary, in
some cases, to road test the
system to determine the specific
complaint.
All electrical and vacuum con-
nections and other obvious items,
such as the bead chain adjustment
and brake release switch adjust-
ment, should be checked and cor-
rected prior to any type of testing.
a. Vacuum, Air Leak and
Power Unit Test
1. Disconnect power unit bead
chain from throttle rod bracket
threaded stud.
IMPORTANT: Check all vacuum
hoses for proper attachment at
vacuum source, power unit and
brake release switch. See figures
11-177 and 11-178.
2. Pull Electro - Cruise engage
lever to the off position.
3. Note position of power unit
diaphragm pull rod.
4. Start engine and again note
position of power unit diaphragm
rod. Movement normally indi-
cates leakage through the vacuum
orifice and control valve. If
maximum movement is noted, the
wiring harness connector should
be temporarily disconnected from
the power unit to eliminate the
possibility of an electrical prob-
lem. If diaphragm rod still moves
into power unit disassembly, in-
spection and repair of the power
CONTROL
VALVE
VALVE
SPRING
FILTER
ELEMENT!
CONTROL
HALF ASSEMBLY
RETURN
SPRING
DIAPHRAGM
ASSEMBLY
COVER
f
L
SC
SCREW (8)
\ FITTING &
BEAD CHAIN ASSEMBLY
Figure 11-179—Exploded View of Power Unit
unit will be required. Paragraph
11-23, subparagraph "c'\
5. With engine still running and
bead chain still disconnected, push
cruise engagement lever forward
and hold. If power unit diaphragm
rod moves into unit, proceed with
Step 6. If rod does not move into
unit, remove wiring connector
from power unit. Using jumper
wires, ground one terminal of
unit and connect the other termi-
nal to a 12 volt source and again
observe diaphragm rod with en-
gine running. If unit does not op-
erate, remove hose which goes to
brake release switch and plug
release hose fitting on power unit.
If power unit still does not oper-
ate properly, it is defective and
should be repaired.
6. With power unit diaphragm rod
pulled all the way in unit by engine
vacuum and engagement lever held
forward, clamp off vacuum source
hose. Leave hose clamped and
engagement lever held forward
for 90 seconds. Any outward
movement of rod in this period
indicates leakage in the hose con
nections, in the brake release
switch, in the power unit dia-
phragm or through the power unit
air orifice and control valve.
7. If leakage is noted, remove
hose from the brake switch re-
lease hose fitting at the power
unit, plug the release hose fitting
and repeat Steps 5 and 6. If dia-
phragm rod now remains station-
ary for 90 seconds, leakage is
indicated in the brake release
switch or hose to it. If diaphragm
rod still moves outward and all
hose connections and conditions
of hoses are okay, the power unit
12-V
BATTERY
BOTTOM VIEW
OF RELAY
NON-PULL-IN
TEST
Figure 11-180—Relay Non-Pull-in
Check