Cruise Control occasionally stops...

[altreed]

Amongst a couple of electrical anomalies that have just started..... I have experienced my cruise just stops working. I pull over, turn the engine off and start again it is back working again. No other errors on the dash. The engine spins over fine and does not indicate a weak battery. I dont use the car very frequently, but the battery is holding up or seems to be.

My other window and wiper issues appear to be related to fuses according to recent postings, I will address them when I get a chance.

Back to the cruise issue, could this be a fuse related problem?

[MBManInKen]

I don't think a fuse is a likely cause. I think a faulty brake light switch can manifest itself in this way, though.

[Mark300SL]

Originally Posted by MBManInKen

I don't think a fuse is a likely cause. I think a faulty brake light switch can manifest itself in this way, though.

That was my first thought - brake light switch, but given the age or the car I would also consider checking the wiring to the cruise control amp, stalk and possibly the amp itself for dry joints in the solder

Teh amp i have shows distinct signs of heat cycling and dry joints so I have reflowed all of them in the hope of preventign any future isssues.


Mark
(currently retrofitting 124/W140 Hybrid cruise to a 190 )

[Dieselman]

Also check the wheel sensor wiring and stator rings.

[alibally]

cruise control cutting out can be sometimes due to tyre diameter especially at 60mph plus. If the tyre sizes are all ok then even one new tyre and 3 worn ones can cause this problem. A brake light switch problem would normally bring the traction light on.

[altreed]

I do have different front and rear wheels on it at the moment, without matched tyre profiles etc.

[Dragon]

I last experienced it 3 years ago on older model(mine 2001), something to do with the battery? - no, something to do with the tyres? - no, more than 60mph? -yes, older model before 2004? - yes

[BTB 500]

Originally Posted by altreed

I do have different front and rear wheels on it at the moment, without matched tyre profiles etc.

Plug the details of your wheel/tyre setups into one of the many "rolling radius calculators" available online. A discrepancy between rolling radius front/back can definitely give CC problems.

[Anil]

Originally Posted by alibally

cruise control cutting out can be sometimes due to tyre diameter especially at 60mph plus. If the tyre sizes are all ok then even one new tyre and 3 worn ones can cause this problem. A brake light switch problem would normally bring the traction light on.

This is the problem I am having with cruise because of incorrect tyre width. The problem manifests itself between 65-75mph.
I'm putting new tyres on the back this week - hopefully this will cure the problem!

[Bazzle]

Wont be the width, its the height (diameter).

http://www.miata.net/garage/tirecalc.html

Bazzle

[BTB 500]

Originally Posted by Bazzle

Wont be the width, its the height (diameter).

Think the two are linked i.e. putting a wider tyre onto a rim can increase the rolling radius (diameter). There's an online calculator somewhere that takes this into account, I'll see if I can find it later.

[rhjcamp]

I had exaclty this issue with my 2001 CLK convertible, and according to the dealer it was all down to an incorrect bulb rating in the rear light cluster. It only happened over 70 mph, you could get it to cruise at 80mph as long as it was on the flat, as soon as you hit a hill it would turn off.

If I remember rightly it was the rear running light, which had a 5w rather than a 4w element?

[Dragon]

Originally Posted by rhjcamp

I had exaclty this issue with my 2001 CLK convertible, and according to the dealer it was all down to an incorrect bulb rating in the rear light cluster. It only happened over 70 mph, you could get it to cruise at 80mph as long as it was on the flat, as soon as you hit a hill it would turn off.

If I remember rightly it was the rear running light, which had a 5w rather than a 4w element?

Is the rating supposed to be 5w instead of 4w?

Where can I get a 4w rating?

[Bazzle]

Originally Posted by BTB 500

Think the two are linked i.e. putting a wider tyre onto a rim can increase the rolling radius (diameter). There's an online calculator somewhere that takes this into account, I'll see if I can find it later.

That is what I posted in the linky above your post The 2 are linked only if profile is not changed.

Bazzle