Help please Urgent?

[mikrt]

So I was disconnecting my 2013 W204 aux battery to charge overnight, but the earth wire I disconnected glanced the live cable underneath it (Uppermost black cable with red sleeve below battery cables) Connecting the battery relay control module.

After the spark and lots of cursing, Half the electronics seem to have failed.

Plugged in my new iCarsoft but the port must be dead as it stays off. Ignition comes on and starter spins continuously but not firing up, and a "Rear left side marker lamp" eror flashed up twice, but is now off.

Please see photos

I'm hoping it's only a fuse blown, any help very greatly appreciated as car needed for work in morning.

 

[grober]

You may have blown one of the fuseable links [ large capacity fuses] that supply various blocks of electrical equipment. If so its not a quick fix. These fuseable links are located on the front prefuse unit beside the battery at the front.
item 264
BATTERY,STARTER/ALTERNATOR CABLE MERCEDES C 220 CDI (204008)

 

[Jockcl500]

Looks a bit odd like it should have a cover over the module, the arcing on the module it is probably fried/shorted out, are any burn marks visible?
if the earth lead is not connected to the battery, it sparked without the earth lead connected, power and earth coming from the starter battery to create/complete a circuit.
My guess is a new module needed.

 

[mikrt]

Thanks grober,

Is this the unit you're refering to

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?

 

[mikrt]

Thanks also Jock, do you think go straight for a repacement relay? Taking the prefuse apart looks a pain.

Since original post, mrs reminded me we pay a fortune to RAC and never use them, so they're now on the way, due in an hour. I don't honestly expect them to sort mind it but my fingers are crossed.

 

[Jockcl500]

Thanks also Jock, do you think go straight for a repacement relay? Taking the prefuse apart looks a pain.

Since original post, mrs reminded me we pay a fortune to RAC and never use them, so they're now on the way, due in an hour. I don't honestly expect them to sort mind it but my fingers are crossed.

Good luck mate, fingers crossed.

 

[mikrt]

I found this on ebay (from E class but same part number) looking @ pic 4 there's a 100a fuse, but on mine it is not there, it disappears under the rear seat I think (I guess to the prefuse already mentioned.)

MERCEDES E CLASS E220 W212 2012 A0009822023 BATTERY RELAY MODULE | eBay

 

[grober]

Thanks grober,

Is this the unit you're refering to

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Yep that's the unit. AFAIK Mercedes don't supply individual fuse links* but usually replace the entire unit
* they can be obtained but difficult to locate a supplier

 

[Joderest]

did RAC sort or pass it on to dealer

 

[mikrt]

No sign of them yet

I guess as I'm at home, I'm low priority.

 

[grober]

ANOTHER VIDEO of a Mercedes prefuse unit and a link to USA amazon supplier
https://www.amazon.com/dp/B01LBJN64U/

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DON'T KNOW IF THESE FIT? Blue Sea Systems Ami/midi Safety Fuse Block 7720 for sale online | eBay
YOU CAN ALSO SEARCH UNDER MEGA FUSES
MEGA FUSES | eBay

 

[mikrt]

Just come off phone with RAC, still 40 mins to go!

Thanks for that Graeme, I found some on ebay too, I wasn't sure if it was midi or mega fuses I was looking for. Is it deffo Mega? Cheers

 

[grober]

Just come off phone with RAC, still 40 mins to go!

Thanks for that Graeme, I found some on ebay too, I wasn't sure if it was midi or mega fuses I was looking for. Is it deffo Mega? Cheers

The only thing I can suggest is to check the dimensions of the existing fusible links if indeed this is the problem- easily checked with meter.

 

[mikrt]

Well RAC just departed - not fixed. That's 3 hours 35 mins wait!
He checked all the spade fuses he could find, disconnected & reconnected the main battery.
I pointed out the pre-fuse, not expecting him to touch it, and he didn't, but said he would have done if it was dry daytime.
Mrs has a lift to work tomorrow and next chance I'll have to get at the car is Tuesday. I'll try and confirm fuse size from work tomorrow and order a few in (both sizes if I have to)
Thanks all, I'll report back, hopefully with a new battery fitted too.

 

[mikrt]

Update; I've bought 3 MIDI fuses, 80A, 100A & 150A off eBay - Only £6.60 including 1st class post (99% sure that's what they are, but they WILL fit!) Bought a battery relay control module, £14 offer accepted, again off eBay. I've also bought a new battery, gone for an 18Ah 230A AGM (it's a bit taller than original, but should fit if rubber pad under clamp is removed) so hopefully after Tuesday, that's the last I see of it!

 

[grober]

this may help
https://fuse-box.info/mercedes-benz/mercedes-benz-c-class-w204-2008-2014-fuses-and-relay

the fusible link f159 seems to be the one to check first but there will be others?

 

[mikrt]

Thanks again grober, I've now ordered a 200A midi fuse. Lucky you noticed, the youtube clip must be non stop/start?

 

[mikrt]

OK THANKS TO YOU ALL!

It was the MIDI/AMI 200A prefuse.

I was up too early this morning (after a 4 x 12 hour day long weekend shift!) with my gloves, hoodie & head torch on (Note to self; next time I break car, do it on dry ground & facing the outside light)

It was a fiddle, but with the help of you lot, google & youtube it's sorted.

I couldn't have done it without you.

The relay just arrived in the post, the seller accepts returns, so I'll send it straight back without opening.

 

[grober]

Glad you got it sorted. Me-- I would hang on to that Relay you bought just in case the existing one got a bit of a "fright" during the incident?

 

[mikrt]

"Glad you got it sorted. Me-- I would hang on to that Relay you bought just in case the existing one got a bit of a "fright" during the incident?"

Do you know what? I was thinking the same.

After all this, and fitting a new battery, I still have an orange "ECO" light. I wonder if the relay could be the cause, or would I not be able to start the car?