battery connected wrong

[dax121]

it was late at nite when i went to move the car. its not being used so i take out the battery. i picked up the jeep battery i had their and put that into it. not looking at what i was doing when it was dark and connected it wrong. it gave out a loud spark so i disconnected it straight away. but when got the right batt their is no lights or even the steering lock wont turn off

[sinewave]

Well at least you didn't try and start it!

That could well have fecked the Alternator!

A quick blast with a reverse polarity should only have activated a safety device.

Cheapest option would be to call the AA/RAC etc if ya in them and have Home Start.

Tell em you're a **** when he gets there, make him a brew and you should get it fixed or at least a free diagnosis.

[dax121]

id say it blew something because when i put in the right battery their was no power reaching the dash or ecu. so cant connect it to a laptop to see whet the fault is

[panason1c]

Originally Posted by sinewave

A quick blast with a reverse polarity should only have activated a safety device.

:

In the old 'non-electronic dependent' days, you would have got away with a reverse battery connection but in this case, there is potential for major damage to have been caused. Hope i'm wrong though.

[panason1c]

Here is a link to a similar situation as yours..........

Mercedes SLK 230 Komp.. Battery Connections? - Yahoo! UK & Ireland Answers

[DRBC43AMG]

So, it does look like a fried ECU. That's not looking good (for the wallet)

[panason1c]

As a long shot........contact your insurance company and ask them if the 'accidental damage' you inflicted on the car is covered under your policy?........you might get a pleasant surprise (or not!)

[Howard]

But then when you set it on fire , they will know why

[neilrr]

How can it be that in the old pre-electronic-everything days MB were able to devise a very simple & almost free protection system for mishaps such as this (the blade fuse in a an OVP) & yet here we are 20 odd years down the road & they apparently have no protection system in place to protect gizmos costing thousands of £££££s.

This could write off an older car!

Who is the genius who made that decision?

[HERBIEMERCMAN]

jump starting can cause your ECU to be damaged due to transient voltage spikes, even with the correct polarity, the flatter the battery the larger the spikes. my brother had his supra mk4 in for repair and they kept jump starting it, the replacement ECU 2nd hand was £650.
most cars have a reverse polarity fuse, but this only protects the wiring, anything which carries the current, fuses only protect wiring, they cannot protect the load, a spike can get through the fuse in a split second before the current melts the conductor in the fuse.
there is an element of luck involved and somtimes you can get away with it, you should have difficulty connecting the leads the wrong way so the voltage sparks should stop you quickly and limit the potential damage, as a general rule the resistive loads will be ok as they are not polarity sensitive, but any solid state items are at risk, in particular the full bridge rectifier in the alternator.

the battery does not care as it's worst failure mode is heavy cranking very high current flow over time which can distort and short out the plates. hope this helps. herbiemercman.

[brucemillar]

Has the OP confirmed that he has checked ALL the fuses yet?

[Williamwoo]

Originally Posted by panason1c

In the old 'non-electronic dependent' days, you would have got away with a reverse battery connection but in this case, there is potential for major damage to have been caused. Hope i'm wrong though.

I got away with doing it on my W124 (an older less-electronic design of course). Perhaps I was lucky - hope you are too.

[donubenz]

You can buy an extension lead with a "spike" eliminator to use for computers so the electronics involved can't be much in the overall cost of an ECU or am I missing something here? Always thought a simple diode only let current flow one way and I know they are easily fried in alternators from bitter experience with an electric welder and an unconnected alternator!
Don

[dax121]

all fuses were checked their all ok. i hooked up the battery today and the milage on the clocks show up but nothing else. so im thinking it mite be the ecu that got fryed. if so ill just scrap the car as it will be too expensive to fix

[Syras]

Originally Posted by dax121

ive checked all fuses they are fine. and the relay that i taught would be for the battery seems to be for the fuel pump. part number A0025421319 V23134-B52-X336.

I've been away and come back to a flat battery on my SLK 2001 compressor, I've then opened the bonnet attached my booster pack and tried to crank the engine, no joy, so I took a look at the booster and noticed I'd connected the leads wrong way round, and now I have a car with no ignition lights and it also won't crank over, please help me somebody