Cruise control not working!!

[jp williams]

brake light switch?

I think so too.

 

[Shaunm41]

I think so too.

This may be a daft question, but if the switch was faulty, wouldn’t the brake lights not work aswell?

where is the switch and is it easy to replace?

Reading some of the posts online about cruise control, a lot of them relating to tyres seem to indicate that the cruise control works for a brief time then cancels.. where as mine just doesn’t work at all, just the 3 dashes flash up then go off.. the limiter works perfectly tho

thanks..

 

[Naraic]

This may be a daft question, but if the switch was faulty, wouldn’t the brake lights not work aswell?

where is the switch and is it easy to replace?

Reading some of the posts online about cruise control, a lot of them relating to tyres seem to indicate that the cruise control works for a brief time then cancels.. where as mine just doesn’t work at all, just the 3 dashes flash up then go off.. the limiter works perfectly tho

thanks..

The brake light switch does lots of things not just the brake lights. It's the switch that alerts the car that you have depressed the brake pedal...it can cancel cc, you must press the brake to move from Park etc etc.

 

[davidsl500]

You may of course have more than one issue with why the cruise control does not work.

The start point is still the wheel/tyre combination as you presently have a difference of 8% rolling circumference. The recommended difference is 1.5% and cruise control will not work with more than a 3% variance.

Put your registration into https://www.blackcircles.com/ and see what comes up for sizes

 

[John Laidlaw]

I’m with the others on tyres

 

[LostKiwi]

+1 for tyres.
Definitely the wrong sizes.

 

[Shaunm41]

Thanks for all the replies.. I will look into the sizes and have them changed for correct ones in the next few weeks..

Thanks for the replies

 

[Botus]

re tyres you could test this for 40p

pump up the small ones (40psi) and reduce the pressure in the tall ones down to 15psi and see of it behaves.... only need to be doing 30 mph, if it works, within 1/2 mile drive back and pump them up again

many cars with cruise get two brake light switches as a failsafe (either dead don't allow the cruise)

 

[Shaunm41]

re tyres you could test this for 40p

pump up the small ones (40psi) and reduce the pressure in the tall ones down to 15psi and see of it behaves.... only need to be doing 30 mph, if it works, within 1/2 mile drive back and pump them up again

many cars with cruise get two brake light switches as a failsafe (either dead don't allow the cruise)

thanks, I’ll try that tomorrow and post the results

 

[Botus]

of course you'll need to get the difference in size enough the car notices.... or borrow two wheels the same from one of the many interesting paces that do wheels and tyres

 

[John Laidlaw]

re tyres you could test this for 40p

pump up the small ones (40psi) and reduce the pressure in the tall ones down to 15psi and see of it behaves.... only need to be doing 30 mph, if it works, within 1/2 mile drive back and pump them up again

many cars with cruise get two brake light switches as a failsafe (either dead don't allow the cruise)

Great tip!

 

[Bogdan D]

Is automatic gearbox?

 

[mioba]

If the OP was to spend money on everything thats been mentioned here it will cost a small fortune.

I would get the codes read and take it from there. Where are you based. Have you a good indy nearby?

 

[Shaunm41]

Is automatic gearbox?

yes it’s auto

 

[Shaunm41]

Well I tried the tip of lowering the pressure in the rear tyres and the cruise control worked.. so thanks for that..

New tyres it is.. I’ve looked on black circle and they recommend the following for 18” rims

front - 225/40R18
Rear - 255/35R18

Does that sound about right?

 

[SL63 Mark]

Wheel-size.com lists 225/40 ZR18 front and rear for the 2003 CLK 270 cdi.

 

[davidsl500]

You need to check the rim widths first! Normally on staggered tyre setups the rim widths also vary - for example 8" fronts and 9" rears. Because your wheels may be off a different car they may be all the same and thus you may need the same tyres all round. So first things first, check rim size and ET on each wheel..

 

[Shaunm41]

Thanks.. I’ll have the wheels off over the weekend and check the sizes..

 

[mioba]

I would go a step further and make sure you first have the correct size rims on the car and then the correct tyres.

I would pop to the dealers and ask, then source the rims and hopefully tyres off ebay then flog your current set to make the money back.

Sometimes if your lucky the online vin decoders will confirm the original setup

 

[davidsl500]

Chuck you vin in and see if the wheel sizes are listed https://www.lastvin.com/