I could not find the answer to this question on a search. My 79 300sd cruise control "almost" works. When you set it at any given speed, it drops 5 miles an hour over the course of about 45 seconds and will continue to drop at this rate.
What is the possible cause of this?
Thanks
Eric Z

Eric,

I'd search again and really read all the posts. I haven't fixed my cruise control yet, so I can't speak from experience, but I've seen posts that talk about several different symptoms including what you're describing. Mine would increase in speed and then slow down. Now it hardly ever works at all. If you manage to get your problem sorted out, please post the results.

__________________
Dave
1995 C280
1999 Triumph Daytona 955I - my speed fix.
1982 300TD - Gone, but not forgotten.

I may be way off, but it sounds like a vacuum leak. My vacuum system leaks very badly and cruise control will not hold speed at all.

vacuum seems like a viable possibility. There is a tube connecting to that bulb thing in the front. I will explore further.
eric