Battery/starting trouble

I've read these posts for a few years now and some people here are very smart about BMW's. I'm hoping you can help me.
As I understand it, BMW's are known for electronic troubles. I have a 1988
735i with about 145k on it. It's had good maintenance since the first owner, my brother in law, had it. He owns a foreign car repair shop on the Jersey Shore. I got the car from him in 2001. I don't know what new batteries it had before then, but I finally had to put a new one in about 6 months ago. My father is good at electronics and he determined what was needed.
I used it every few days (we have 3 cars extra) and it ran fine. about two weeks ago, I noticed that all of the dome, door, etc. courtesy lights were on even if the car was shut tight. I've had many troubles with this car in the electrical system. I had to put in a new box that feeds current to the headlights because one kept going on and off sporadically. (maybe that's the trouble now. LOL)
Anyway, we trickle charged the battery but even the dashboard radio lights were still dead. The charger can't keep up with the lights draining it. I then attempted to start it but when I got the key to the ignition position (one step before where you'd be cranking) and a loud buzz came from under the left back seat (all the relays I think, since the battery's on the right side). It sounded like it would do damage if I left it on, so I turned the key back to the off position. When I did that, all the lights went off like they should have since I had shut the door tightly when I got in to try to start it. But even in the off position, the terrible buzz continued.
I took the key out of the ignition and got out and shut the door, but the buzz continued. I then pulled the plug on the trickle charger unit and the buzz finally stopped.
My father wants to try to charge it again, but I can't believe that the buzz is not harming the car if it's left on for hours. I think he believes that the buzz will stop if the battery gets charged enough but that didn't happen the first time.
Has anyone had this problem? I plan to have AAA tow it to a local shop near Cape Canaveral since the mechanics there are honest and good. The nearest dealer is in Melbourne, about an hour south and they charge much more.
Nothing else is wrong with the car that I can see. The dashboard display often stops and all the needles go down to zero and at night, the lights would go off as well. They want $1,000 to replace that. I said NO and all I do is smack the right top/side and it fires up each time.
I hope someone can give me an idea about this. I trust the dealer, he's had many chances to do work that was not needed and he's never done so. His reputation here is good.
BTW: If anyone here is looking for a good foreign car mechanic ( I don't know all the models he fixes), he's on Tropical Trail on Merritt Island, FLA.
Thanks in advance for any assistance.
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Thomas King wrote:

Hi Thomas ... with the miles on the car and the erratic electrical pattern, my first guess would be the ignition switch ... your key lock is just fine ... there is a bit of plastic and metal box behind the key that sorts out all the electrical pathways ... about 6 of them I seem to remember get hooked up to the wire loom.
Have to logic path the electric battery to ground thingy .. and find out what something it NOT getting electricity ... usually have to wait until something is broken all the way. Not so intermittent and ghostly like it is now ... not really failing yet ... but soon on the way.
But this would be my best guess ...
sumbuddie hopes that helps
:?
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near Cape Canaveral since the mechanics there are honest and good. The nearest dealer is in Melbourne, about an hour south and they charge much more.

Thanks very much for your help. When I posted this, I was hoping you might answer since I understand you're an expert on these cars. I couldn't recall your name but I knew I'd recognize it if I saw it. I love the show Family Guy and McFarland I think does the voices.
I moved here from Jersey 4 years ago and every mechanic who looked at the car told me it was in great shape and to try and maintain it. It is costly but it's never left me on the side of the road. I always get plenty of warning. My brother in law had this car for his own family car until he got a one year old Lexus for $5,000. The engine was blown so all he did was drop another one in and he had a $60k car or whatever it costs. Florida has a lot of autobahn type roads (empty and clear and straight) so if anyone wanted to see how fast his car went, better here than New Jersey.
The dealer told me if I ever wanted to unload it, he'd be interested. If any new things go wrong that start to really cost, I'll have to sell it. Oh, and the Florida sun has baked the tan/beige paint off of it. I could have waxed it better but it's still like living in an oven.
Thanks again and many years of safe driving to you.
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wrote:

Bwaahahahahahahahahahahahahahahaha! That's friggin' hilarious!!!
The guy is actually a total nitwit and occupies no small number of killfiles here. But you go ahead and follow his advise (if you can decipher any from his special form of gibberish) because this group could use the humour ;-)
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Bob Allison wrote:

keeping one's head under the shifting sands of deception is a harsh discipline and hard work I must add ...
no expert on cars here, just have a good idea about people.
if you think I have good ideas, fine with me.
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