electrical faults

[dbknh]

new to the forum, new to the car (530i,2004 e60 idrive). I saw a couple problems last winter... dead battery for no apparent reason, but starts right away on a jump. I've had it a year, and thru the summer I saw no further problems. However, it's getting cold again (New Hampshire) and I've started to see the instrument cluster cycle through the fault icons when I start it... i.e. transmission fault,and others. If I turn the car off and restart it, it'll start up ok with no faults. Once in a while the Idrive and dash instruments go out, dome light goes out and then they all come back on. Last year the dealer (Nashua, NH) said fault codes during the winter season are a common problem and are frequently associated with a weak battery. I just replaced the battery (Nov, same type from Battery Plus), I suspect it wasn't ready to be replaced, but it also ensures a weak battery is not a contributing factor. The real question here is... are other people seeing this kind of problem on a regular basis (cold and seasonal). I'm fairly technical, but really new to the world of BMW.

[962porsche]

one of my cars is a 1985 E23 735i 76k miles . when it gets bitter cold the lights for the check-control do come on at times for no reason . the OE stock radio will also make a pop sound throw the right front speeker when i step on the brake . 15 years ago when i got the car i cleaned all the chassis grounds i could find and it did work fine for 2 winters but came back . i now only drive the car about 100 miles a year and never in the winters .