Milano Cruise Control

[KURT6507@domain.elided]

Instructions for repair of Milano Cruise Control
These instructions worked to repair my Milano CC unit and have been checked
and approved by a VDO technician.

Alfa Romeo CRUISE CONTROL
There are three major components in the CC system: the control unit
(amplifier),    the Amplifier, the Transducer and the Actuator  Servo unit.

Amplifier: This device compares the actual speed of the car and the selected
speed. In the event of a deviation from the selected speed the control unit
sends pertinent control signals to the electrically actuated throttle servo
unit until the actual and selected speeds are again in agreement.

Transducer: The transducer sends the actual speed signal to the Control unit.

Actuator: The Actuator is an electric unit that adjusts the throttle, via a
motor to an appropriate setting to maintain speed. Check that the linkage is
secure.

System Checks:

In order to trouble shoot the system, you should have a digital volt-ohm
meter, some tests leads with alligator clips, plus straight and
Phillips-head screwdrivers, metric wrenches, and a trouble light.
But first of all, check the obvious  is the fuse blown?  Don9t just LOOK at
the fuse rotate it back and forth in its spring holder to assure clean
connection at each end. Check it with a meter.

Important:
DO NOT USE THE U.S. TYPE 1157 BULBS  THEY CAN DAMAGE THE CONTROL UNIT
BEYOND REPAIR!
If you are not sure, check that the brake light bulb in each tail light unit
of your car is an original equipment OSRAM or BOSCH bulb. The correct bulbs
are available from Alfa parts suppliers.

If the speedometer works, it9s a good guess the speed signal from the
transducer to the Cruise Control unit is OK.

The next area to check would be the brake and clutch pedal interlock
switches. There is a switch for the clutch pedal just like the switch on the
brake pedal (for the brake lights). This type of switch has three terminals.
The clutch circuit uses only two (C & NO) while the brake switch uses three
(this ensures the ARC will flash the red warning lamp if you have a burned
out brake lamp or a bad brake switch, it also checks the switch, but has no
way to tell you of a bad switch!)

 The logic is this; both pedals in rest position, (and switches adjusted
correctly, Closed) signal to CC unit is ground via the rear tail lamps if the
clutch pedal is pushed, the circuit goes open and the CC unit will release
and or not engage. If the brake pedal is pushed, the circuit goes to +12V and
again, the CC unit will release or not engage. You can check this circuit
without pulling the CC unit out of the dash. Open the hood and carefully
disconnect the CC actuator unit cable. You have to squeeze the connector to
pull it apart. With a DVM, you can check the switches. First put the meter in
the DC voltage range appropriate for 12V. Do the following test on the red
wire in the connector coming from the firewall with relation to ground. With
the ignition OFF, and the pedals at the rest position, the voltage should
read zero.  Next, have an assistant push the brake pedal, the voltage should
now be 12V and the brake lights should be ON. Finally, have the assistant
push the clutch pedal should remain 12V. Also press the clutch pedal, brake
pedal released; the signal should go to 12V.
Next check the resistance of the circuit, relative to ground, with both
pedals in the rest position. Keep the meter leads where they are (red + to
pin 4 red wire and black - to ground) and switch the meter to read ohms. The
reading should be a few ohms. Again depress the clutch pedal, Ohms reading
should be near infinity.


Cruise Actuator Checkout
Here are some very rough checks that can be done as follows:
Disconnect the cruise actuator cable from the plug located on the firewall.

Using a VOM, check for continuity at the cable pins as follows:
Pin 1 and 2: about 2 to 10 ohms
Pin 1 and 3: about 2 to 10 ohms
Pin 2 and 3: about 2 to 10 ohms

CAUTION: Do not touch 12 volts to pins 1, 2 or 3, or you will permanently
damage the actuator.
Using 2 jumper wires connected to the battery, test the motor by momentarily
touching positive to pin 4 and negative to pin 5 the motor should run
(reverse the wires and the motor should run in the reverse direction).
Momentarily touch + to pin 6 and - to pin 7 the clutch solenoid coil should
make a clicking noise, indicating it is working.
These checks will usually detect stripped gears, faulty circuit contacts or
worn motor bearings, although the motor should run smoothly.

If all that shakes out OK, you may have a bad CC unit or a bad servo unit.

Finally, the CC unit is "in" the center console just about under the radio.
Not easy to remove.  At the plug, the wiring is:
        Pin #1 (yellow) to servo Pin # 2
        Pin #2 (black) ground
        Pin #3 (wht/blk) to servo Pin # 6
        Pin #4 (red) via pedal to servo Pin # 4
        Pin #5 (lt. blue/blk) resume signal,
        Pin #6 (gry/ylw) decel/set button
        Pin #7 (grey) speedo signal
        Pin #8 not used
        Pin #9 (wht/red) to servo Pin # 3
        Pin #10 (lt blue) to servo Pin # 7
        Pin #11 (green) to servo Pin # 5
        Pin #12 (grey/blk) to power "off" relay, normally 12V,
        Pin #13 (pink/wht) power on with key,
        Pin #14 (grey/grn) accel/set button,
        Pin #15 not used.
Note: Should Surging occur, check that there is a small amount of slack in
cable when at rest.

Hope this helps all who need it.
If you have any questions, feel free to E-mail me as I have become quite
comfortable with the system.

Kurt Incledon
kurt6507@domain.elided
87 Milano Gold (Mickie) Now with working Cruise Control
86 Spider (Rickie) No cruise, but happy non-the-less

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