turbo_mustang12

So I have a 2005 545i with about 83,000 miles on it and I have been having problems with the alternator charging. I have replaced the alternator and the battery twice and still the same problem. I currently have a brand new valeo alternator on it. As soon as i picked it up from the mechanic I drove about 5 miles and when I exited the freeway I was waiting at the light and the abs light, all the dash lights starting coming on and the radio started sounding funny etc. At this point im really frustrated and dont know what to do. The mechanic told me I had a draw and it was coming from the ccc because when he disconected the ccc the car would put up 14 volts and when he plugged it in it would drop to like 8 so I changed that and im still having the same issue. Sometimes the car pulls 14 volts and sometimes it does not. I know a few people have had this issue on another forum so if anyone could help that would be great. The mechanic is now telling me that I need a new engine harnesss. Before I drop 1200 on a new harness do anybody know if that can be the issue?

ktlocklear

The battery has to be registered with the car's software. Was this done? I have read on here if this doesn't get done charging issues could possibly occur.

545felix

I am having the precursors to this issue. I would check the ground points and make sure everything is OK; check (or disconnect) the IBS; and currently my leading suspect is the blower motor resistor, which I think is shorting out and causing all sorts of havoc when it does. I don't think you should replace the harness just quite yet.

turbo_mustang12

Thanks guys. All of those things have been checked. Any other possibilities? Anybody else having this issue??

akgolfpro

Make sure your trunk is dry!

turbo_mustang12

Actually my trunk was leaking once but i fixed that. Any part in general your talking about being "dry"

545felix

have you tried disconnecting the "intelligent" battery sensor and seeing if the problem disappears?

turbo_mustang12

Felix no I have not what is that and where is it located? So your saying take that off and drive the car without it?

545felix

it's the small lead connected to the negative battery cable. yes, you can drive without it. the only risk you run is that if a component decides to stay on, it will stay on until your battery's drained. the IBS stops that.

turbo_mustang12

How can i check the ibs and the blower motor resisotor? I would rather check it my self since none of these mechanics seem to know much. i drove it yesterday and it started failing again the radio started to sound distorted, all the error messages came up and the car was stuck in one gear. Thanks for your help felix