Electrical problems

[shaylpn99]

Ok I start my car and nothing electrical works. I turn my car off then back on and everything works. Any ideas. Also my lights will only work in the parking lights setting.

[iDontRemember]

How’s your battery?

[shaylpn99]

Car starts fine.

[iDontRemember]

That doesn’t necessarily mean the battery is good. Mine was starting fine but starting it would put a large drain on it and it was slow to recharge (alt was putting out), what was making me nuts was the ac blower fan would stop working at stop lights. I wish I could claim to understand BMW’s charging logic, but I can’t and I’m too lazy to learn it.

[shaylpn99]

I’ll get the battery checked

[nachob]

Originally Posted by shaylpn99

I’ll get the battery checked

Can't hurt to check the battery.. It sounds more serious than battery but that is one the first places to start. I recently started to get an ABS and brake light on my 330i and everyone said it was ABS speed sensor so I plugged in the OBD reader and saw a fault of ABS Voltage not present. Again I googled it and everone said either ABS sensor or speed sensors. I contacted my German mechanic friend since he gets me a deal on parts and asked him to order me 4 wheel sensors. He said that seems extreme. Did you test them. He told me I can do a live test and see the readings on my BMW OBD scanner. While poking around looking for the live test, I came across the car voltage and it said 11.9V. I thought OK it's close enough and car starts fine. I found the live testing and all four speed sensors reported the correct speed. Then it clicked. I only got the error in the morning. Never in the middle of day or evening. So next morning I plug OBD before starting and voltage is 11.6V. Car starts fine but ABS and Brake lights come on. So I go clean battery terminals and see battery is from 2012. I figure it's old enough I just replace it. Immediately voltage went up to 12.6 volts and it has been a week and not single ABS or Brake warning.

So the battery can cause some systems to shut down overnight if voltage drops and after running the car and restarting the voltage can go up enough to reset things. So while this unlikely, the first thing to check is the battery.
Make sure you check the voltage in the morning before you start it. It should be around 12.2-12.5 volts. Mine was having issues at 11.6 volts in the morning.

Let us know what you find out please. I have a feeling as our cars age, we will see more of this and useful to share information.