Bmw e9 ignition electronic issues..need advice. Connected battery backwards.

[verde2002]

So yesterday while trying to jump start my 1971 2800cs I was distracted by a conversation and connected the booster cables backwards and didn't realize it until the alternator wire started smoking and the wire jacket melted. This all took about ten seconds. I waited a minute or so, reconnected the wires correctly and turned on the car but that only lasted about 30 seconds and car shut off on me. What is really interesting to me and maybe someone can answer this is now the car won't crank at all and more bizzare is the fact that when I have the key twisted all the way to the starting position it doesn't spring back one click like it should once car is on. The key twists all the way and stays there. Again the car won't crank, the "L" light stays on even though the key is not in the ignition and my passenger side power window stopped working. I did look at all the fuses under the dash and they were all good. Where should I loook? Which relays might have gone out? Why does my key twist all the way and not return a click like it should have?? Any help would be appreciated.

 

[jhjacobs]

This doesn't sound good. Based on the description it sounds like you may have melted the ignition switch contact housing (which has the little return spring mechanism for the switch). This might also explain the non-functional windows and engine quiting after 30 seconds - the contacts may be badly burned and giving up quickly under load.

On a '71 there aren't too many things that will completely die with reverse voltage. The most likely are the alternator, regulator and the turn signal relay. Your case sounds mainly like burned alternator, maybe some fried wires and the ignition switch contacts.

I think the ignition switch contactor assembly is buried pretty deep in the steering column. I haven't pulled one for decades. There may even be a rivet to drill out in the process but my memory went on me years ago; they say it is the second thing to fail... No, wait, when I was born God gave me a choice of a good memory or a big pee pee -- I don't remember what I chose. :confused:

Good luck. I think I have a spare working alternator or two and maybe even some old regulators. PM if interested or for moral support.

 

[verde2002]

You are correct, I checked the ignition switch contact housing and it has seperated from the metal and all the springs have popped out. How do I repair this? Do I need to buy a whole new ignition switch? Are they even available to be purchased? I really would love to use my original key if possible. Can I just replace the contact housing? Thank you.