Cruise control fault diagnoses W126

[Alex Crow]

factory fitted actuator on this 420 would have been on a bracket mounted on the alternator hanger. if you look at the aluminium casting there will be a lug that would have been used. some of the retrofitted kits were done by dealers when cars were brand new, and usually had the actuator wing mounted with a bowden cable.

 

[Onne]

Mine is definately not on the inner wing like yours, but then again its a different engine.
I'll take the air box off tonight for a look, hopefully not too much LPG related stuff in the way!

 

[ianrandom]

Hmm sorry for the misleading info then.

And thanks Alex, i had no idea it might be a dealer fitted option.

 

[Alex Crow]

it is still highly likely to have the same electronics pretty much.

i have worked on the cruise control on a dealer fitted kit on a 1988 w124 that used the same control unit, stalk etc as factory fit, but with a remote actuator.

 

[ianrandom]

Yup the stalk and everything else all look completely normal. How funny.

 

[Onne]

I've just had delivery of a "known working" set, but it is slightly different. How far are the parts interchangeable (as long as I replace all parts)

I think the one sent to me is for a late '86 model, mine is '90.
Item code 003 545 07 32 for the '90 model
Item code 003 545 05 32 for the '86 model

Also got the stalk, which seems to have a nice click, unlike the one currently fitted.
Are they known to go pop? (even though is the ECU 99/100 times)

 

[television]

They are both the same part, one is newer that is all

 

[Onne]

Thanks Malcolm, they look quite different that's all.

Do you happen to have the instructions to replace the cruise control stalk?

Cheers

 

[Onne]

Hello all, the quest continues...
Is there a way if testing if the cruise control works whilst stationary?

Also there is a loose connector under the steering column, two pin female.

Last but not least, how does one remove the steering wheel?

 

[Onne]

We're a cruisin!

As you all said it was the ECU, and I can a acknowledge that earlier versions are compatible.
Shame it wasn't the first ECU I tried!

Thank you all for your help!

 

[television]

So CC how nice

 

[Onne]

It was nice while it lasted... Cruising along today, and all of a sudden the cruise control stops working again...

Does that sound like (yet another) ECU failing on me?
Are these repairable with an insertion of Maplins goodies?

 

[television]

I do have one here from a 140, it is hard to know what fails on them if it is the amp, it is said that can be the caps ageing, but I could not find any that were bad on the one I have here.

You can post to me one of your old boxes if you wish

 

[Onne]

That would be great Malcolm, can you email me your address? I'll try and send it later today then. Email is thanks Malcolm!
Thanks again

 

[television]

All sent, I can check what I can in the cold state

 

[Onne]

I'll send it first class today.

Cheers

 

[Onne]

Well, the replacement (earlier version) ECU seems to work every now and again...
Worked fine for the 10 or so miles on the motorway at a steady 65mph, stopped at my local motorfactors for a cam cover gasket, and no more cruise control.

Do these things get hot, and thus too hot to work?

Cheers

 

[Onne]

Back from holiday in (suprisingly) sunny Herefordshire.

Cruise works every now and again, especially after hard braking. Is the brake light switch a sensitive one? Brake lights seem to go on ok?

Cheers

 

[Onne]

Hello all, apologies for the ongoing whinge...

Cruise control is still consistently inconsistent. Is it possible to be the switch or would this again point towards a loose wire/connection within the amp?

Thanks!

 

[Onne]

Hi Malcolm, sorry to contact you this way, but did you manage to find out anything through the cold state?

the earlier type I had has given up the ghost...