manual transmission BMW 5 SERIES 1981 E28 Cruise Control

Test at ECU Plug

Component/Circuit
Result

4. Ignition on—check volt-

age at Terminal #5.
Control switch RESUME.
Move lever to RESUME.

Voltage jumps 0 to 12V.

If not, check wiring and

switch.

5. Measure resistance Term-

inal #3 to ground. (Auto

transmission in neutral.)

(Ignition off.)
A.) Automatic Trans-

mission

B.) Manual Trans-

mission
A.) Approximately 4

B.) < 1

6. Apply voltage to term.

#8 and ground term. #9.
Actuator solenoid

(Clutch)
Listen for click in actuator

7. Measure resistance

Terminal #8 to ground.
Actuator and clutch

switch.
Resistance approx. 30

Press clutch pedal, then

resistance = oo

If not, check wiring, clutch

switch, and brake lights.

8. Apply voltage to term.

#13 and ground term. #25.
Actuator motor

Listen for motor running.

9. Measure resistance

Terminal #24 to Terminal

#23.
Actuator potentiometer.

Resistance approx. 3000

If not, check wiring/

replace actuator.

10. Measure resistance

Terminal #23 to ground.
Ground
Resistance = 0

If not, check wiring and

ground.

11. Measure resistance

Terminal #26 to ground.
Actuator.
Resistance approx. 3000

If not, check wiring/

replace actuator.

12. Measure voltage at

term. #9 (Ignition on)
Brake light switch
0 Volts then depress brake

pedal voltage = 12V.

61-09/3

FOR CRUISE CONTROL TO BE ENGAGED

PIN 9 MUST SENSE GROUND THROUGH

STOPLIGHTS.

WHEN BRAKE SWITCH IS CLOSED OR

CLUTCH SWITCH IS OPEN, GROUND IS

ELECTRONICALLY REMOVED.

CRUISE CONTROL ELECTRICAL SCHEMATIC
BRAKE

SWITCH

CLOSED WITH BRAKE

PEDAL DEPRESSED
POWER

DISTRIBUTION

BOX

CLUTCH

SWITCH

OPENS WHEN

CLUTCH PEDAL

IS DEPRESSED
POWER

DISTRIBUTION

BOX

AUTOMATIC

TRANSMISSION

RANGE SWITCH
AUTOMATIC TRANSMISSION

CRUISE

CONTROL

SWITCH

C210

CRUISE CONTROL

CONTROL UNIT

TRANSMISSION

RANGE

DISPLAY

TO THROTTLE

VALVE
FEEDBACK

POTENTIOMETER
INSTRUMENT

CLUSTER

CRUISE

CONTROL

ACTUATOR

CLUTCH

SOLENOID
CANCEL RESUME ACCELERATE/

SPEED SET SPEED

CONTROL INPUTS
INSTRUMENT

CLUSTER

MANUAL

TRANSMISSION
IDLE

SPEED

CONTROL
FUSE 6

8 AMP

POWER

DISTRIBUTION
POWER

DISTRIBUTION

ACCELERATE/

SET
OFF RESUME
OFF
S217 C206 S309 C301
.75 GN/WT

.5 VI/WT C210 GN/WT

CLUTCH CONTROL CONTROL MOTOR CRUISE

OUTPUT OUTPUT ENABLE

SEE DASH LIGHTS
GROUND
"N"

OUTPUT

BAND
1.5 GN/WT

1 GN/WT
11

1 GN/WT
.75 GN/WT

.75 GN/WT
1

.75 8U/3R

.75 BU/BR
S234
3

15

1

2

D

6
N
R
P

S
W
0

GN
BU

.5 YL
.5 GN

.5 BU

4
5
SPEEDOMETER

SOLID STATE

2

C8

.5 BU/YL
CRUISE CONTROL

CONTROL UNIT

POWER INPUT
.5 VI/WT
C250

STOP LIGHTS
.5 GN/RD

.5 GN/RD
MANUAL

TRANSMISSION
AUTOMATIC

TRANSMISSION
C208

.5 GN/RD
C208
61-09/5

S224
.5 GN/RD
.5 GN/RD
9

G200
.5 BR
SPEEDOMETER
.5 VI/WT
1.5 VI/WT

S241
FUSE 12

8 AMP

.5 VI/WT

VEHICLE SPEED

INPUT

CRUISE

ENABLE

.75

BU/BR

C8
GROUND
FEEDBACK

REFERENCE
FEEDBACK

INPUT
SOLID STATE

24

26

.5 GY/RD
.5 GN/YL

4

.5 RD
7

.5 YL

.5 BR

3

S233
(-)

12

16

C1
C6
.5 BR

.5 BR

G200
.5 BR
.75 BU/BR

6

7
.75 BU/BR

.5 BU
C209
.5 BU/WT

2
3

G200
13

.5 BK

5

.5 BK
.5 GN
.5 WT

.5 WT
CONTROL

MOTOR
1