Merc FTP - Cookie's adventures in shiteing

[Cookiesouwest]

I f*cked up a bit.

Went to car. Indicator still on.

Battery protection still on.

Started the engine, as im paranoid about the battery going flat again, then set about removing the wing mirror cover. Its a pain, but eventually it came off.

Definately water inside the light.

Once it was off, got a warning for the indicator being disconnected.

But the battery protection warning had gone !!

Either a co-incidence, as I had had the engine running and may have charged the auxillary battery. But a long drive this morning hadn't done that, so I dont believe that. I think the indicator had a short that was f*cking up the electrics.

The new indicator was shit and wouldnt fit. As if the chinese engineers had seen an original but hadnt bothered measuring it or even test fitting.

I dont have a dremmel but I do have a pen knife

After about 45 mins of whittling plastic, it fits. Kind of. I also had to enlarge one of the screw holes.

This is how much I took off, from various places.

The puddle lamp connector is also wrong and wont fit.

Old correct one on left. New wrong one on right.

So I tried getting the pins out and swapping the connector. 

I did but pressed the pin into the new connector the wrong way and now its stuck fast.

So I will need to sort that at some point.

When it stops pishing down, I will refit and see if error comes back.

 

[SiC]

The aux battery on it is one I fitted brand new.

I have recollection that it's charged differently to the main battery. As it's designed for emergency use when the main battery is flat, it spends most of its time not being used. So, from memory, the charge circuit is done separately to the main battery. This charge circuit can only slow charge the battery. Which is fine as it rarely has any power drain.

But that means it will take ages to fully charge from flat as that shouldn't normally ever need doing. 

Personally if I wanted to make sure it was fully charged, I'd have taken it out and put it on a separate charger with it set to motorbike battery mode. 

[Cookiesouwest]

Went out tonight to refit the mirror indicator and maybe the aux battery.

Car was dead as a Dodo again. Wouldnt unlock on key.

Im surprised its gone from starting ok with good battery charge to dead flat in 20 hours.

Too cold to piss about tonight with it, so will have a go tomorrow.

 

[SiC]

Either the main battery is dead/dying or there is something not shutting down and causing a high power drain.
I suspect it's something not shutting down

[Cookiesouwest]

25 minutes ago, SiC said:

Either the main battery is dead/dying or there is something not shutting down and causing a high power drain.
I suspect it's something not shutting down

I suspect the same.

Im going to remove both batteries. Fully charge them. If it dies within 24hrs, then its not the batteries.

[drewd]

Not 100%  sure if this is your issue, but it's worth investigating. Some Mercs have an electronic heater booster to help improve warm up times. It's basically an electronic heating element that draws something like 30 amps.

On my w203 C270 CDI this unit is bolted to the engine block, above the starter motor and below the inlet manifold. Which makes it a royal pain in the arse to access. Fortunately on other models it's mounted in more accessible places such as the inner wing. On mine the positive battery cable goes to this heater booster and the alternator, there's no fuse to disconnect so it took me a while to find out it existed and was faulty. Mine went open circuit and was killing a fully charged battery in about 6 hours. At first I thought my battery died as it happened during a cold snap in December, but it killed the brand new £150 battery in 6 hours too! I disconnected it and insulated the cable, it's been fine for almost 3 years now.

As I say I'm not sure this is your issue, or where the heater booster would be on your model, but I'd look into it. A quick google search found this video, not sure if it's of any help but it looks like it could be in the boot?