Cruise control

[cclake]

My 1984 380sl surges when using the cruise control. Does anyone have any sugestions. Also do you know where the electronic module is located. Thanks

[Strife]

My cruise control module caused this symptom before it failed entirely. However, lubricating and adjusting the linkages is worth trying - if these are misadjusted or tight, they can cause the same symptom with a perfectly good cruise control module.

[Roncallo]

Originally Posted by cclake

My 1984 380sl surges when using the cruise control. Does anyone have any sugestions. Also do you know where the electronic module is located. Thanks

Well there it is right there by the brake pedal. Just disconnect that connector remove those two little screws (he he he he) and pull it right out.

[David Langsam]

I shouted a year's worth of obscenities removing and replacing that effing thing.

These people fixed it up for me. They know their stuff. Seven or eight years ago, it was about 100 bucks, probably more today. They even improved it by smoothing out the response. It still works perfectly today.

http://gdl-online.com/begin1.html

Later on, I read you can remove the board from the housing in place and not bother removing the screws. Never tried it because I never want to go near that thing again.

David

[pwogaman]

I have successfully resoldered two cruise control and two climate control boards. It is really not hard at all, just open the case and touch each connection (solder point) with a small hot soldering iron until the solder boils; add a little more if needed. Make sure the solder does not run on any nearby connections. Take your time, there are about 100+ points to hit.

The surging comes from a weak connection where the solder cracks and does not send a signal until it reaches a higher amperage, and by then the speed will have dropped sufficiently that the system surges to get back up to the set speed. Works pretty much the same with other conenction problems. My 85 300SD system would have given me whiplash if I keep using it as is.

This link is to a picture of a point I subsequently redid. You can actually see the cracking, but just because you can't does not mean it is not there.

http://www.peachparts.com/shopforum/attachments/diesel-discussion/46327d1185425015-diy-page-introduction-resoldering-climate-control-unit-100_0445-failure-point-.jpg

Just touch the hot tip on there until it melts and the crack is gone!

This link is to a DIY resoldier thread.

DIY page. Introduction to Resoldering Climate Control Unit

[cclake]

Found a pretty good leak on the intake manifold yesterday so I have to fix that before I go any further.Maybe next weekend