CLS - tales of electrical woe

[Lotusgone]

Tried starting the old girl this morning (CLS500 55 reg), dash lit up but the engine wouldn't turn. Out with the battery charger - boot won't open. Tried the manual key, it wouldn't budge. WD40 later, still no joy.

I now have a car where I cannot access the boot to boost the battery, what's more, the key won't shift in the ignition either. Central locking won't work.

I would be grateful for any suggestions. Is there a clever way of accessing the boot by shifting the back seats?

[Sheepshanks]

There's usually a jump start point under the bonnet, with a red cover. There is on my C Class. I connect my charger there.

I have it in my head that some models might have it in the passenger footwell.

Does the CLS have two batteries? I don't know if that complicates things.

[Lotusgone]

Thanks for the suggestion - there was a separate charge point on my old BMW540. I was looking in the manual for something similar, nothing obvious but will investigate further.

[goldieandblackie]

Will the boot not open using the key blade!

[Lotusgone]

goldieandblackie said:

Will the boot not open using the key blade!

Sadly not - as mentioned, the manual key will not budge the barrel.

[goldieandblackie]

How about lubing the boot lock and lube the key as well then try again.

[Lotusgone]

Will give it a go, to see if that will work where the WD40 wouldn't.

Failing that, would replacing the auxiliary battery reboot the electrics to allow access to the boot?

[Defconluke]

Hopefully you've got it sorted by now but if not then simply turning the blade in the boot lock won't open it, you have to actually pull the handle once the blade is turned too.

That's how it works on my 2007 CLS although I don't know if it is any different if you have an auto closing boot (I can't imagine why it owuld be though).

[Lotusgone]

Unfortunately the blade key won't budge at all.

Apparently a new auxiliary battery will open up the electrics, which should then free up the boot. I'll give that a try.

[Deefor62]

I had the same issue with a 320CLK. Couldn't open the boot with the key, and no amount of WD40 and a hammer on the key would shift it. I suspect the key lock hadn't been used for years, as the boot was always opened via auto opening function on the key fob.

I manually opened the drivers door, opened the bonnet and attached jump leads to the positive power point in the engine compartment, and the negative to something solid.

This then enabled me to open the boot via the key fob, and get access to the duff battery.

I would be very surprised if your CLS doesn't have a positive terminal in the engine bay.

Hope you get it sorted, as it frustrated me considerably..

[Lotusgone]

Thanks - I had seen from some googling that the CLK has a positive terminal, but cannot find any reference to it for the CLS.

If any CLS owners know where it might be found, that'll be very helpful.

[Stegel]

Our 06 diesel doesn’t have a positive terminal under the bonnet either. Your car is an early one with two batteries, our car has only one, in the boot. Could you connect up to the auxiliary battery? I believe it lives in the scuttle?

Does your car have a boot release switch in the driver’s door? Our car does not have a power operated boot, just the standard “manual” operation. It just activates a solenoid to release the lock, and I can’t imagine needs much power to trigger it. We have had the car since new and it wasn’t an option, but MB do change features year to year, and there was a mini facelift very shortly after launch.

Edited by Stegel on Saturday 27th February 14:13

Edited by Stegel on Saturday 27th February 14:14

Edited by Stegel on Saturday 27th February 14:16

[crispian22]

If the alternator is accessible can you run the positive to the back of that just to get enough volts to open the boot?

[Nath911t]

Did you get this sorted out? Take the key out and rotate it 180 in the boot lock then turn the key and pull the handle to open it at the same. That's what I had to do with mine.

[Lotusgone]

New auxiliary battery arrived, went to put it in; a word to the wise, always make sure that your battery terminals are compatible with the battery...new battery has the normal round cylindrical points - the old (and original) one has some bracket and screw affair.

Car to be trailered to a local independent specialist this week...