Hooked up jumper cables incorrectly

Hello everyone. Hate to admit it but I was working in the dark (in sub zero temperatures) up here in Northern Minnesota and accidently hooked up my jumper cables incorrectly. Have never done this before EVER until now. I noticed the sparks and smoke and quickly unhooked the cables but it was too late. I do not see any visable damage to the vehicle or battery itself, but I cannot get the vehicle to start. I have check many fuses pertaining to starting the vehilce and havent found a blown one. The battery is charging and holding its charge as well. The dash, radio, display, lights, etc all are working normal. The vehicle will only "click" when I attempt to start-wont turn over at all. Does anyone know what else I should look for? I have other vehicles so I havent been driving this one since it happened (about a month ago). Worked on it in the cold all afternoon and cant get any results. Even ran some heat on the engine block and battery to warm it up (its outside in my driveway). The car is a 2002 BMW 325xi. Would be battery be toast after 3 seconds? Alternator? Starter? Any input would greatly be appreciated. Thanks.

Auto or manual? If manual try giving it a push start and see what happens.

well you could have done some damage but...

it sounds to me the battery doesn't have enough charge to start it still if its clicking. i would jump start it again but the right way. or likely replace the battery.

the Alternator charges the battery and/or runs the car after its started, so the alt has nothing to do with it not starting.

There is probably a fuse you blew

I believe there are two cables running from the battery. A small one to supply almost everying on the car, and then a large one to hook into the starter and alternator supply. Sounds like you're not getting voltage to the large cable.
Test the voltage at the large cable on the back of the alternator to confirm my theory.
Could be there is a large fuse on this large cable.

There are also fusible links located behind/above the fuse panel in the glove box that require a screwdriver to change and there is an explosive disconnect on the big positive cable from the battery to the starter. One or more of these could be blown. You also could have blown some electronics modules in the car. It is not uncommon for expensive modules to blow first to protect the 25 cent fuse.

There is, I'm almost certain, a large fuse...50-100 amp hiding somewhere. This has happened before.

One thing...were you jumping from the trunk or hood? I don't know where this fuse is, but someone will know. Not in e-box, I don't think. Might be behind the fuse panel...but hang on...I'll see what Bentley says...

brb

Okay, main harness fuse...200 amp...behind liner by battery...little wire feeds into one side of the fuse...main cable keeps going past. Bet it's that.

There are large fuses behind fuse panel...see 102 (80 amp) B+ term/DME mail relay/ECM/Fuse pack in e-box (hmmm...see if you have power there...if not...could be this, and 105 (50 amp) ignition switch

If you're getting a click, start by charging/jumping the battery. Click indicates starter circuit is still intact, which means no blown fuse.

Originally Posted by lcoleman

If you're getting a click, start by charging/jumping the battery. Click indicates starter circuit is still intact, which means no blown fuse.

Not so fast. Two sources for power to starter. One directly from the battery for the motor, and the other from the ignition switch for the solenoid.

Originally Posted by Stinger9

Not so fast. Two sources for power to starter. One directly from the battery for the motor, and the other from the ignition switch for the solenoid.

I'm aware of that, yes. The click is from the solenoid engaging, which means the ign switch is getting power, which means EWS is getting power, which I believe means the CAN Bus is getting power. Please feel free to correct me with wiring diagrams, I am always open to learning.

The fusible link shouldn't be blown from a brief short.

Originally Posted by lcoleman

I'm aware of that, yes. The click is from the solenoid engaging, which means the ign switch is getting power, which means EWS is getting power, which I believe means the CAN Bus is getting power. Please feel free to correct me with wiring diagrams, I am always open to learning.

The fusible link shouldn't be blown from a brief short.

Well, we don't know the facts yet, but we can discuss can't we!
I think all your conclusions in your first paragraph are correct.

But you say a brief short. Technically this is not a short, but connecting one battery in series with another with low resistance heavy cables. That would give the potential for an immediate pulse of upwards of 500A! Takes a fuse out in milliseconds.

i have already given the next step in diagnosing what is wrong. you're in the cold in MN so im inclined to think it's still the battery. although you say it's charging and holding a charge are you sure? just because the light and dash go on doesn't mean it has enough CCA to start the car. a low battery will light the dash lights.

next for those thinking it's a fuseable link or the battery cable fuse, if this is burned out tell me how the car is getting power for the dash, radio, lights and display??

the clicking sound is the solenoid for the starter. it can either be not enough power to start it or next would be the starter is faulty. if doing a proper/correct jump start doesn't get the car started and you're able to push start it (if manual) then it leads that the starter is likely the culprit.

do things simple and in order of likely suspects before doing other hunts for possible reasons. right now that is eliminating the power source for the car to start. Battery.

Likely you have a bad starter, you were obviously using jumper cables because the engine would not start before the cables were hooked up backwards.

For some reason the xi cars seem to eat starters more often than other cars and the starter is a real PITA to replace.

Try to get a hammer and bang on the starter, however, the starter is very tough to reach in these xi cars.

If you get the car started, make sure your alternator is not damage and is charging correctly.

Most components in the car have protection diodes that will cause a fuse to blow if reverse polarity happens. If your battery was fully charged, likely you did not get a chance to actually damage anything if you were quick to remove the backwards cables.

Haha, I had "connect two batteries in series" then erased it. Technically it is a short, because the circuit is closed! The first pos > neg connection was in series. The next was a direct/dead short.

Perhaps the best course of action for OP to to check continuity between pos battery and the underhood jump terminal if possible. I can't remember the exact location of fusible link, but I believe it's between those two.

If not, just charge/jump and try again.

Alex is right...charging battery is best. If jumping, keep them on longer...rev donor car for 5 mins, and if it starts, don't stop for about 30 mins...it'll take some time to restore the battery.

Uhm, op does all your interior&trunk lights turn on?

This happen to me in texas and weeks if not days when giving someone a jump start and cable miss connected for few sec 2-5

Some reason: battery leaked : starter went out so did the alternator few weeks after the starter got replaced

Moral of self experience story : if you do not know how old Battery or when last replaced starter & atlernator plus/ bearing

Id just replace it all. $100 battery ( 3/5 year warranty )

Try bmaparts.com other parts:
2cent
sent from phone to bimmer app

Hey everyone. Thank you so much for your time, knowledge, and suggestions. I could've sworn the battery was fine (it was virtually brand new-just a few months old) because everything was lighting up and working. Turns out I just replaced with another new battery and it started right up. It appears that three seconds of my error was enough to destroy a $165 batttery! The car runs and drives just fine. I love these BMW's. Lesson learned I guess. No matter how much of a hurry Im in, no matter what temperature, I will at least make sure I am working with a light! Thanks again to you all and enjoy the rest of your weekend.

Gee, I wonder who said that from the beginning. And kept telling others this when they were going all over the place.

Originally Posted by alex323ci

gee, i wonder who said that from the beginning. And kept telling others this when they were going all over the place.

+1.