BMW Repair: ?electrical problems 1994 bmw 325i, remote control car, bmw 325i

Question
I have a 1994 BMW 325i.  Recently I have put about $3000 in it and it hasn't fixed the problems.  First time, as I was driving I noticed the lights dimming, the radio was going in and out and then after a couple of miles and going up a hill the transmission light, ABS, Traction Control lights came on as well as the gauges going crazy.  I pulled over and when I put it in park the car idled rough.  I turned the car off and then after trying to restart it I was unsuccessful.  I had it towed to a repair shop and was told I had a bad transmission.  It cost me $2500 to rebuild the transmission.  When I picked it up it seemed to be working fine for about 2 weeks.  Then, it happened again, same thing.  In the meantime I had taken it to another local repair shop because my check engine light came on.  They told me it was an oxygen sensor light.  After it stopped for the second time I called the guy who rebuilt my transmission because he told me that was the problem in the first place, but, this time he told me he knew it wasn't the transmission and to call the place I had clear the check engine light which came back on because I didn't get the o2 sensor replaced.  I had it towed to the second repair shop who at that point found a loose battery ground but said the battery and the alternator checked out fine although when the car first arrived via tow truck the battery was definately dead.  He told me it was being cause now by the lose ground.  Satisfied with this, another $200, I left and 3 days later it happened again, luckily in my drive and there it still sits.  What is weird is when I turn it off when this happens and starts idling rough I can turn on the acc power and can listen to the radio, etc but when I try to start it, it just ticks.  But, let it sit long enough (couple of hours or overnight) it will start again with no problem.  It reminds me of a remote control car that you have to recharge when the battery dies except to recharge it I just have to let it sit.  We did get the alternator changed about 3 months before it quit the first time and that is when the check engine light came on, after we changed it.  I also notice, every time before it happens, the AC will start blowing hot air, the lights will dim (headlights and interior dash lights) and the windows, etc work slowly.  Please, help, I'm sick of this car!!

Answer
I think you should find just one shop and stay with that one.Having multiple people on it causes multiple problems as everyone thinks they know the answer.
If you know what one problems answer is you should fix it.You have "found" loose grounds,I would start there> Clean and tighten all your grounds,if the battery ground strap is green at all replace it.Another tip: the wires corrode internally,which means you won't actually see the wire broken.It will look whole and not broken the clue is if the wire casing is bumpy it is an indication of trouble.