[s-cars] Cruise Control

[bill mahoney]

"Is there anyone who can e-mail me diagrams of the cruise control schematics
for our cars?  Either I have the wrong box, 12 pin connector silver box made
by Hella mounted up by the firewall/passenger side kick panel, right by the
servotronic; or they changed the part between '91 and '92, as my 200 Bentley
shows it as an 8 pin box.  I am in dire straits as I need my cruise for a
LONG trip.  Thanks!"

Calv,
It IS a 12 pin harness connector to the control module to test.  If
you look directly at this harness holding it with the connecting wires
on top, the top row is positions one through six and the bottom row is
seven through 12.

Cruise Contol trouble shooting Leak Per Bentley:
Check fuses 9 and 14
Check brake lights function ok

Leaks in vacuum-
Disconnect vacuum hose from vacuum pump.
Press in diaphragm on actuator
Plug end of disconnected vacuum hose
-Diaphragm actuator must remain in position
IF 
Diaphragm moves back into position, there are system leaks.
If Diaphragm remains in position go to electrical tests.

on aformentioned 12 pin connector:
Connect multimeter between terminal 8 and 5
Cruise control switch ON.
Drive vehicle 20mph
zero volts = break in wiring or replace switch
12 volts = go to B
B.)
Connect multimeter between terminal 8 and 10
Push switch towards RES position
infinity ohms = break in wiring or replace switch
zero ohms =go to C
C.)
Multimeter to terminal 8 and 4
Press FIX/SET button
infinity ohms = break in wiring or replace switch
zero ohms = go to D
D.)  Switch for vent valve for brake pedal faulty or break in wiring.
Connect multimeter to terminal 11 and 5
Move switch to ON position
infinity ohms = replace switch or vent valve for brake pedal or repair
break in wiring.
zero ohms = go to E
E.)  Vent for brake pedal
Connect meter to terminal 11 and 5
Positon switch ON
Operate brake pedal
zero ohms= replace brake pedal vent valve
infinity ohms = go to F
F.)  Vacuum pump motor faulty
Switch iginition ON
Connect ground to reminal 6 of control module connector.
Supply voltage to terminal 7 using jumper cable.
IF motor does NOT run-
vacuum pump faulty
replace or fix break in wiring.
IF motor does run, go to G.
G.) Vent valve in vacuum pump is faulty
Switch ON ignition
Connect ground repeatedly to terminal 12 of control module connector.
Supply external voltage to terminal 7 using jumper cable.
IF valve does NOT click-
vacuum pump faulty.  replace or fix break in wiring.
IF valve DOES click-
Check speedometer speed signal  

HTH and also, I could be hallucinating but IIRC (and I could very well
be wrong) there may be some kind of connection either vacuum or
electrical up under the expansion tank or somewhere along the driver
side inside fender well to check also.

good luck
Bill M