engine BMW 7 SERIES 1986 E23 Cruise Control With Electric Acutator
Page 10 of 14
CRUISE CONTROL SYSTEM TESTS - 733i (VACUUM SERVO)
A. Vacuum - Check fit and condition of all vacuum and vent lines.
B. Electrical
TEST AT ECU PLUG
COMPONENT/CIRCUIT
RESULT
1.
Measure
resistance
across term. 1-12
push car min. 2 feet
Reed switch in differen-
tial
and
wiring.
Resistance changes 0 to oo
to 0, etc. If not, check
wiring and switch.
2. Ignition on. Check
voltage at term. 5.
Power supply.
Voltage - 12V. If not, check
wiring.
3. Start car. Jumper
term. 5-3 and then
12-7 momentarily.
Servo
Servo should activate and raise
engine speed. If not, check
wiring and Servo.
4a. Ignition on (not
running). Check
voltage at term. 6.
b. Ignition off. Check
resistance terminal 6
to ground.
System disconnect
circuit.
Adaptor ground.
No voltage. Push brake pedal
then voltage = 12V, or trans.
to 'N' and voltage = 12V. If
not, check wiring, switches,
and adaptor.
Reading approx. 20 to 150
Now reverse leads and reading
must remain between 20 and
150. If reading is at oo
with either hook up check
adaptor grounding or replace
adaptor.
5. Ignition on. Check
voltage at term. 8.
Control switch OFF.
Move lever to OFF. Voltage
drops from 12 -> 0 volts. If
not, check wiring and switch.
6. Ignition on. Check
voltage at term. 9.
Control switch CONST.
Move lever to CONST. Voltage
jumps 0 to 12 volts. If not,
check wiring and switch.
7. Ignition on. Check
voltage at term. 10.
Control switch RESUME
Move lever to RESUME. Voltage
jumps 0 to 12 volts. If not,
check wiring and switch.
If these electrical tests are OK, then change the control unit if the system does not
operate correctly.
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Page 12 of 14
CRUISE CONTROL SYSTEM TESTS - 633CSi (VACUUM SERVO)
A, Vacuum - Check fit and condition of all vacuum and vent lines.
B. Electrical
TEST AT ECU PLUG
COMPONENT/CIRCUIT
RESULT
1. Measure A/C voltage
across terms. 11-12.
Car on hoist in gear
and running.
Signal Generator and
wiring.
10 mph approx. 0.7 V A/C
20 mph approx. 1.4 V A/C
30 mph approx. 2.1 V A/C
40 mph approx. 2.8V A/C
2. Ignition on. Check
voltage at term. 5.
Power supply.
Voltage - 12V. If not,
check wiring.
3. Start car. Jumper
term. 5-3 and then
12-7 momentarily.
Servo.
Servo should activate and
raise engine speed. If
not, check wiring and Servo.
4a. Ignition on (not
running). Check
voltage at term. 6.
b. Ignition off. Check
resistance terminal
6 to ground.
System disconnect
circuit.
Adaptor ground.
No voltage. Push brake pedal
then voltage = 12V, or trans.
to 'N' and voltage = 12V. If
not, check wiring, switches,
and adaptor.
Reading approx 20 to 150 .
Now reverse leads and reading
must remain between 20 and 150
If reading is at oo with either
hook up check adaptor grounding
or replace adaptor.
5. Ignition on. Check
voltage at term. 8.
Control switch OFF.
Move lever to OFF. Voltage
drops from 12 -> 0 volts. If
not, check wiring and switch.
6. Ignition on. Check
voltage at term. 9.
Control switch CONST.
Move lever to CONST. Voltage
jumps 0 to 12 volts. If not,
check wiring and switch.
7. Ignition on. Check
voltage at term. 10.
Control switch RESUME.
Move lever to RESUME. Voltage
jumps 0 to 12 volts. If not,
check wiring and switch.
If these electrical tests are OK, then change the control unit if the system does not
operate correctly.
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