DESPERATE HELP! Cruise Actuator
 

The cruise on my 85 300TD suddenly stopped working a few days ago. I immediately noticed the cruise actuator in the engine compartment was "clicking" whenever I turned on the ignition key (and not using the cruise stalk) before the car actually started. If I unplug the cruise box, the clicking stops. I have done the following without any idea what the problem is.

1. Replaced the cruise box with a rebuilt known good one from our buddy "JamesDean".
2. Tested power to each pin at the box from the stalk.
3. Tested actuator at plugin.
4. Replaced the actuator with a known good one to be certain (checked by James Dean).
5. Exchanged the computer module on the passenger kick panel (only on 85 models).

The problem remains with the actuator ticking away whenever the ignition is on (even before the car starts). I need someone smarter than I to help as I am out of ideas!!!
I just spent 2 hours searching the net with no answer. This is a known problem, but there are NO solutions found!

Richard

Check your brake lights and tail lights; a burned out bulb might create a problem.

James Dean offers, at no charge, an easy to follow step by step fault isolation procedure. It requires a voltmeter.

IRT the tail light bulb, true dat. The cruise uses stop lamp activation to disengage.

If the stop lamp bulb does not have the proper resistance the cruise control will not operate.

Cruise control schematic and component layout
 

Recently, I repaired my 1984 300tdt cruise control. I reverse engineered
a schematic and was able to repair and bench test the unit. Works fine now.


If you wish, send me your email, and you are welcome to what I have. Please
note that there maybe some errors, but all in all it should assist you if the
fault is in the electronics.


Mariano

Mariano,

VERY interesting! I would SINCERELY appreciate it. My email is benzjag@hotmail.com.

Richard

bumping an old thread, but if possible I would like to get the schematic also.

email: AF5XF@protonmail.com

Thanks, Matteo