CLS 320 CDi 2007 - No response when ignition key turned

[PeteWild]

Hello all,

Time to seek the help of the wise ones again !

Mrs drove car to local shops, no problems starting at home, but when she came out of shops, nothing....

By nothing I mean no noise, no crank of engine, not even the duurrrrr of a dead battery.

Dash lights all light up as they should and go off again dependent on key position, key itself turns freely in the keyhole, its not blocked or anything, just no response

Any ideas as usual gratefully accepted....

 

[PeteWild]

Bit of an update
Had car recovered to home and mechanic (of sorts)/recovery driver reckons it could be one of a few things;
1. Key fob batteries - enough power to open doors but not to start car - Checked and both batteries 2.98v so OK
2. Infared 'reader' that you insert the key into (keyhole in my language) - Not sure what its called or how to test it
3. Starter motor fuse - Ill check when its light in morning
4. Starter motor relay - Again Ill check when its light enough to see
5. Starter motor itself - Might try and jump it, which I've seen online is possible, but not sure if this is wise - Comments / tips how to?

Once again, thanks in advance for your time / help

 

[Blobcat]

They don’t require batteries in the key to disable the immobiliser, it works from a chip in the key which is read by an inductive loop in the steering binnacle.

 

[PeteWild]

Hi Blobcat,
Thanks, I wasnt aware of that, but now youve explained it makes sense.
Is the 'binnacle' the key hole ?
I have a spare key and was attempting to check with that, but same result.
Could it be the reader/inductive loop thats at fault? And do i understand correctly, this is the immobiliser
As I said earlier, Im looking at the fuses and relay tomorrow when its light enough, but in your opinion, could it be the key or the reader?

Im trying to eliminate causes in the order of easiest to replace/cheapest

 

[sonic]

A friend of mine had the same problem with a C class, It was the binnacle a infra red issue, cost £600 at MB to fix.
I am sure someone else reported this on the site a few months back?

 

[Noddy 99]

This happened to me twice. And then I realised I was trying to start it in N, not P. It will only engage the starter motor when in Park...

 

[mioba]

Simply have you put battery on charge. Your wife could have left a light on...

 

[PeteWild]

Hi Mioba,

Not casting aspersions on the Mrs, but that was my first thought, however I don't think its a flat battery.
Willing to be told otherwise or proved wrong, but everything else electrically is fine, and the total lack of 'anything' when I turn the key seems unlike a low/flat battery, normally you get at least a click. I did try a jump start before it was recovered, but for completeness, I will however stick it on a charge just to be sure.

 

[Noddy 99]

You are DEFINITELY starting it in Park, yes?

 

[PeteWild]

Hi noddy,

I wish I could say no it was in Neutral and that would be that, but its in Park

Things I have noticed though

When I insert the key, it makes all the usual whirring and clicking, the steering lock disengages, so would I be right in thinking this means the infrared jobbie has done its duty and read the key?

Im starting to think the problem is further down the line
Cant find a fuse or relay that mentions starter motor on the list that comes with the car, either in the cockpit or the boot fuse boxes but see from looking online, theres one in the engine bay?

Thanks all for your help so far

 

[PeteWild]

Bingo

Found the engine bay fuse box and also thanks to Google the fuse number (59) and lo and behold, its blown !

Now I feel Im getting somewhere

Next plan of action is to replace it and see if it pops again, hopefully its a one off, update to follow !

 

[PeteWild]

Went and bought the fuse, in fact being the eternal pessimist, I bought 5, fitted it and boom we are away again.

Several test starts later, we are all still good, best £1 I spent recently

Once again, thanks for all your help and inputs, I learnt how things work as well, always a good thing

 

[dry run]

Result!

Thanks for updating us.