update on alt change issue, comments?

tonydan1 · #1 12-30-2007, 06:54 PM

Hi All,

Well, got the new alt in and all the lights in the dash went away.

Though, went for a drive today and the humming, low and high humming, is back. I am really stuck now. Several people that can be trusted advised me that it was the regulator in the alt that was defective.

This only happens when the car warms up. On start-up, it is a stable humming noise. Also, with this humming, the lights also dim and go bright, in sync with the humming noise.

Another other experiences or credible facts of similar senarios?

Thanks

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klnteg · #2 12-31-2007, 09:18 PM

sometimes a bad ground will also do similiar to that hummimg noise. Not sure how its set up on the X5 though?

tonydan1 · #3 01-01-2008, 02:24 AM

Ground? Really? Where would I start. I know that there are grounds between the hood and chassis.

Where else?

Thanks

klnteg · #4 01-01-2008, 10:11 PM

Are you runnig any other loads on the circut, like stereo or electronics that are not factory from BMW? If so when did it get installed? Check the voltage out put on the system. If you don't already know how to do it, here's how

take a multimeter and test the battery should be around 12.85- 14.00 volts for a good battery, if your less than that then you have a problem. (get a new battery) start the car and monitor the voltage meter which is attached to your battery. the voltage should go up when car in running. put your headlights and heater fan to medium speed and obsereve the voltage drop. but when this humming comes into play up and down watch to see if voltage of system follows. If it does then the might be a problem with the alternator. I would take it back to where it came from. If it doesn't (which I am certian it will!) then take it to an indy mechanic you trust. Good luck!

tonydan1 · #5 01-02-2008, 09:36 AM

it is weird that it happens only when the car warms up. on start-up, there is not fluctuations. it can be that the regulator is defective. the company i got it from is a good one and they have the machinery to test the voltage, though how can they test when it actually warms up on their machines? I will have to go speak to them about this.

thanks for the info though, it was a good answer.

klnteg · #6 01-02-2008, 09:40 PM

keep us posted!!

tonydan1 · #7 01-03-2008, 05:57 PM

hi,

called dealer and told them what is happening. they are really nice. they told me to bring it in when this issue is happening and they will try to diagnose it on the spot.

i have to check the baterry also but i need to run some tests when it does also on my own before i bring it in.

fast4d · #8 01-04-2008, 11:16 AM

AFTER I swapped teh alternator the red light still came on intermittently. I changed the voltage and it was over 14v at idle. we paid the dealer an hour's labor to hook up to their testing machine. the warning light has never appeared again. who knows if they probably pulled the bulb.

where is this humming? from the speakers?

tonydan1 · #9 01-04-2008, 12:26 PM

hi,

The up-down humming comes form the fuel pump under the passenger seat. Fluctuating of course. This also entails the lights in side the car. but the idle of the engine is stable.

I have decided to replace the battery with a new one. It has been 5 years and before I bring it in to the dealer, I want to get all my bases covered before they touch it. This doesn't hurt.

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