W124 cruise control not working properly

[MercedesintheBlood]

Hi All

Recently purchased a 1991 W124 300E. The cruise control hasn't worked properly since buying the car. I think I managed to get it to work once only for about 5 minutes.

When I hold the cruise control stalk up to set it, it sometime sets but then disengages after 10 seconds, or will sort jerk and the speed will increase automatically.

The stalk seems a little floppy, so not sure if its broken or if it could be something else ?

I have posted a few other threads on this forum for other issues I have with the car, but hopefully I can get them all sorted soon.


Thanks

 

[Wearsthefoxhat]

Hi,

Has it got the correct wheels and decent tyres as this could cause a problem too.


Sent from my iPad using Tapatalk

 

[tron]

Unlikely. If the cruise control is dropping out, check the wiring through all the switch sensors. These should be short circuit when on because they are designed to fail safe and that means a dirty contact or loose connection will cause the problem. If manual, there will be one from the clutch pedal and all have one on the brake pedal. Start there and then check the contacts on the cruise module itself. Check the fuse for dirty connections and then the switch for correct function at the control module. You will need the circuit diagram which is not too hard to find for a 124.

 

[Flyinspanner]

On that age, is it a vacuum system? Could be a vac hose leak?

 

[tron]

Fair point. Check those first.