engine BMW 7 SERIES 1986 E23 Cruise Control With Electric Acutator

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.

61-03/2

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.

61-08/4