Erratic Cruise control R129

[MBFAN]

Hi everyone,

After a little help on cruise control.

Purchased car 2 years ago and cruise never worked. Finally got round to looking at it, removed the ecu/amp and resoldered the dry joints as in another thread. Cruise now works in a fashion, sets above 40kmph, surges when in operation around the set speed. Setting on stalk work as follows, accelerate and decelerate have no effect, off does work and resume does work, although the car does appear to accelerate very quickly to the presumably previously set speed. A little hair raising when used due to surging.

Car is 1992 300sl-24
Wheels / tyres are not original although are genuine MB
Original size 225/55-16 now 255/45-17.

Have used the tyre calculator, again from another thread, and the size appears to be a good exchange.

Any advice or help greatly appreciated.

 

[shirubaby]

maybe you cruise control amp is busted. also might be worth cleaning the contacts on the stalk itself...might cure the accelarate decelrate problem.

I used to have a surging problem on my old w126 but that was with the turn signals being on. Someone fitted a non-merc turn signal flasher relay and I think is was connected to the same ground point as the cruise amp. Remember the amp is ground sensitive...pressing the brake; breaks the ground connection to the amp and knocks the cruise off...that's what i heard.

 

[Telegraph-Hill]

Hello MBFAN,
sorry don't know your name...
The
ecu for the Cruse control can be repaired in 80% of all cases. Klick on "Telegraph-Hill" and send me a mail for more information.

Cheers,
Oliver