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BMW 2005 535d electrical power and computer problems

My BMW 535d seems to be having power issues. While driving the computer fails… I loose all systems… Auto trans, steering, brakes, tire monitor, GPS etc. Sometimes all the indicator lights flash. I need to pull over and restart the car so computer reboots. Until it happens again. Can’t drive fast with transmission in this condition. I notice if I accelerate fast it seems to provoke the reaction. Before this began to happen, the date and time had to be reset after parking the car overnight a few times. I also notice the battery warning light when pulling over to reboot computer. I had it to the dealer now twice. First time they failed to fix it. They just serviced the car. When pulling out of parking lot of dealer it happened again. I brought it right back. Then they replaced a relay switch that they said was hot. That did not do it. I bought it back again. They’ve now had the car four days. This is BMW Dijon, France. Can it be this is a bad dealership? I find it strange that they can not find the problem… esp now that it is easy to cause it to happen. Any ideas?

My best guess would be a failing alternator.
When electronic devices are not given a consistent flow of electrical energy, they will produce all manner of…strange…reactions.

Have the alternator output checked.

Is there some sort of voltage control on this car as well? And thanks for the advice

I seem to have read somewhere there was a ground issue with some of these BMW’s too… do you know anything about that? And thanks again

You’ve probably seen this, and yes, ground problems can wreak havoc on any car: