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3 Series 318 M SPORT 2004 E46 Intermittant electrical fault

1K views 3 replies 3 participants last post by  BIG PEB 
#1 ·
Hi Guys...Help needed please...BMW main dealer couldnt find the fault!...My dashboard lights flicker on and eventually stay on some amber one or two red, Sterio cuts off...windscreen wipers slow down, headlights dim.... and after a while I lose total power, engine idles but cant accelerate, and will eventually cut out...Wont start ie clicking just like flat battery...However, new battery and new alternator on car. As soon as the terminals are touched by jump start it turns over like new, and will run perfectly for a week or so until it starts again. Last time it happened and cut out, I was on M6 with family in car...not a great experience!!
RAC have checked In Put to and from battery and its pushing 14.7 volts both ways and they are at a loss. ANYONE EXPERIENCED SOMETHING SIMILAR?

Hope to hear from you soon

Paul
 
#2 ·
Its probably stating the obvious, but it's more than likely a bad connection somewhere. I would think a major one considering all the things that are affected. I would start at the battery end and work my way forward. Start by taking both battery terminals apart, including the Battery safety terminal (BST) and the ground connection from the negative terminal to the car body. There are quite a few ground terminals on the car and all these are worth checking. You can buy kits on ebay that beef up the ground terminal wiring on lots of cars and many people say that they have noticed a differance.
Bit of a long boring job I'm afraid especially as the fault is intermittant, but if you do it yourself you can save a fortune on labour charges.
Good luck.
 
#3 ·
Was the alternator and battery changed because of the fault or did the fault occur after?

I would 1st check the main connections but I have had a similar problem for a customer who had new stuff replaced it turned out they fitting was at fault. The wires felt tight to the alternator but they had overtightened and the metal connector was twisted resulting in a poor output which was also intermittent. I had to replace the Positive connector and all was fine after that.

If I was you I would be looking at the alternator being at fault. Some do have separate units to control charging as well.
 
#4 ·
Hi Donny Cheers for that, I had the Alternator and battery changed about 8 months ago due to this fault occurring. I did however only replace the alternator with a reconditioned unit...Actually a Bosch unit same as original. It was only a matter of a few hundred yards before the lights flickered on again! Its been happennining at various degrees of severity since then, but started before I had them changed.
I have had a feeling that it may still be a problem with the alternator. And yet the RAC checked both the input and output immediately after my break down and found it to be normal i.e 14.7 volts both to and from the battery?

?????Paul????
 
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