Hi dieselbenz1 - thanks! Hopefully I can get this one going but if not I will certainly let you know. Gotta keep every old part working if possible as they are getting harder and harder to find.

cmac2012 - Yes, mine is a 603. I don't know about having an amp specific to this engine or not. I started with the actuator (under the intake manifold) - I did the glow plugs and was in there already so I took the actuator off and cleaned it all up and checked the contacts, greased the mechanism, etc. Everything looked fine. So the amplifier/module is the other option for failure.

I haven't researched it myself but you can send it out to a place that does what I did but do a lot of them so they really know what they are doing. Probably the way to go.

EDITED: I found a thread on the guy who used to be (or still is) a contributor to this forum Cruise Control repair. Here is his website: https://www.cruisecontrolrepair.com/products-services/rebuilding-service-mercedes-cruise-control-amplifiers-test1

I also found this great info - download the PDF from that website in case it disappears in the future... https://trythistv.com/cruise-control/

__________________
_____________________________________

Chris_87_300D
1987 300D - 415,000+ miles
1999 E320 - 220,000+ miles
2008 SL55
2019 Sprinter Diesel 4x4