ML270 CDI Cruise Control

[stringerdavid@hotmail.com]

Can anyone help/advise, please?

I have just bought a mint 2001 ML270 CDI Auto BUT, the cruise control randomly dis-engages. When working, I get all functionality - but is frustratingly unreliable.

I live in Scotland and am fortunate to have mile upon mile of almost empty motorways - I NEED my cruise control to work - consistantly..!!

Can anyone help, please?

 

[Paul_Churchill]

Cruise Drops Out - some possibilities

David,
I retrofitted Cruise Control to a 190E and the chances are that your system is a variant on the same as I fitted - the most likely cause is the brake light switch or the connection to it - the cruise has a plug that piggy-backs off the connector to the switch and when you touch the brake pedal, the brake pedal arm releases the switch to make the brake light circuit and the cruise drops out. That's favourite but it could be any connection in the cruise harness I'd pull apart and remake all of the plugs and sockets in the Cruise circuit - to the brake pedal switch - to the control stalk - to the actuator on the engine block - to the control unit (under the passengers feet on a 190E)
- to the hall sensor where it gets the speed reference from - the power and earth connections. Another possibility is the control stalk which should be firm ans snappy in operation not rattling - hope this helps
Paul

 

[BlackC55]

Can anyone help/advise, please?

I have just bought a mint 2001 ML270 CDI Auto BUT, the cruise control randomly dis-engages. When working, I get all functionality - but is frustratingly unreliable.

I live in Scotland and am fortunate to have mile upon mile of almost empty motorways - I NEED my cruise control to work - consistantly..!!

Can anyone help, please?

Are your tryes all the same size?

 

[panason1c]

A possibility is that the clearance between the brake light switch and the brake pedal is too fine (or no clearance at all) ...........Next time you are driving with cruise-control on, just very gently put light pressure on the brake pedal without actually depressing it....if the cruise dis-engages each time you try this it would confirm that the pedal/switch clearance is too close.

 

[stringerdavid@hotmail.com]

Thanks for all your help.

Yes, all my tryes are the same size (new).

I have also tried slightly touching the brake pedal - and no disengagement (other that when 'it' decided to disengage of 'it's' own accord - grrrrrrrrr). All other suggested checks proved OK.

I have thrown in the towel - and my ML is now booked into a MB Main Dealer...!!!

 

[panason1c]

Cheers for the feedback....it's always worth investigating the 'minimal-cost' possibilities first, as you have done, before throwing £££'s at the dealers.

 

[alec2]

There was an issue in 2001/2002 on some mercs with random tripping out of the cruise control.

This was usually fixed under warranty.

It involved a wiring loom mod. (It was probably electrical interference.)

You need your fault codes read!

Alec

 

[stringerdavid@hotmail.com]

Can anyone help/advise, please?

I have just bought a mint 2001 ML270 CDI Auto BUT, the cruise control randomly dis-engages. When working, I get all functionality - but is frustratingly unreliable.

I live in Scotland and am fortunate to have mile upon mile of almost empty motorways - I NEED my cruise control to work - consistantly..!!

Can anyone help, please?

Thanks for all your replies. I have GOOD NEWS to share!

I took my car to MERCEDES-BENZ of GLASGOW (Milton Street), who were extremely polite and professional. Having left my car with the Dealership for 2 days, I was informed that at some stage, a fault HAD occured and had been stored somewhere in the cars 'brain'. The 'brain' had been reprogrammed and the car road-tested (over 2 separate days) with no re-occurance of random disengagement. I held my breath and asked for the bill.. I was amazed and pleasantly surprised when I was told - "No charge, Sir"!
So much for the horror stories about MB Dealerships (My previous car was a Jaguar XJ, and can assure you that this does NOT happen very often at Jaguar Dealerships).
Anyway, thanks for all your replies and advice.

Safe motoring to you all.