[Rob.mcdonnell]

Hopefully this may help someone as I couldn't really find a detailed thread on what I needed.
Basically car was fine (07 E93) and I popped into a shop and came out 10 mins later and my car wouldn't start just a click noise. Checked the battery compartment and it was full of water! After taking the battery out I found the 2 pass through terminals in the wheel arch were coroded through and one snapped off in my hand so here's what I did....
This is the wire snapped off..

The positive cable which runs to the starter motor had snapped the negative one was still in place so undo the nut and that will come off aswell, also worth noting the black surrounds just twist anti clockwise and they come off to give you more access to the nut and thread. Also give everything a good clean and get rid of all corrosion.

Next is to cut the corroded section off and re solder and crimp a new connector on.



Then just fix it all back together and make sure everything is fry and clean and in my case the car worked straight away
Hope this helps someone, its very much a DIY job, no need to get ripped off by garages. Or atleast take the cables off and take those to a local garage and get them to quickly fix another connector on.

[Efthreeoh]

I noticed a similar issue on my car, but on the OUTSIDE of the pass trough terminals. The terminals pass through the fender wall to just behind the fender liner. The terminals are protected by body urethane undercoating. The undercoating on my car has started to crack, which lets corrosion seep in. I've not yet worked the problem. It's been several years since I noticed it.

Your post has me thinking I need to revisit the issue.

[ptpending]

this problem burnt many e8x e9x cars , which i've seen on junkyards

[Ecivon]

I had the same issue on my '07 335i cab. E93, N55. Older battery, bought new one same type, found water, dried out, installed new battery. Positive cable had corroded to within 4 inches of other end!
During process, unwittingly tried to jump start car. After battery installation and registration, no audio, no navigation, nothing. The car would run, turn signals worked (no sound), no reverse sensor. Tested all fuses although tester gave bad information. Bought MOST loop kit to test optical components. First component - Satellite Radio. Disconnected and connected MOST loop bypassing Satellite radio, and everything came back to life! (except Satellite radio, of course).
A couple weeks later, no radio again an no audio in car. Am going to run OBD again to see how it changed from prior.
Any users with experience here, help will be much appreciated.