Mercedes 300E cruise control

Hi. I have a 1990 MB 300E. When you try to set the cruise control the speed just keeps increasing, set it at 45mph and was going 80 before I shut it off. Any ideas of the problem and possible fix would be greatly appreciated. Thanks

It’s usually the amp, talk to these guys:

http://www.gdl-online.com/price.html

As I recall, one stalk controls everything. Up or down, forward or back. It is possible that the switch inside is not sending the right message to the amp.

That is also possible, here is a troubleshooting procedure for the switch:

http://www.gdl-online.com/test024.html