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Discussion Starter #1
Hey, so one day out of the blue, I attempted to start my car, and it only clicked 1 time. Got out and knocked on the starter then started right up. That worked a few times and then stopped. Replaced my battery, worked fine until another 1 click. I tested the connection with a test light and my car is pulling 12 volts when the car is off. Had the mechanic replace the starter, thinking it was faulty. Worked fine for a week and then today same 1 click. The only way around this issue is to unplug the positive terminal every time i get out so that the battery doesn't drain. Please help me guys!
 

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you're saying something is draining your battery while the car is off?
What connection did you test and how did the test light give you 12v?

If something is draining your battery you need to do a parasitic drain test. you'll need a DMM for that one.

oh and you always disconnect the negative lead.
 

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Discussion Starter #4
Yeah, I tested the positive lead to the battery with a test light.
Put the alligator clip on the positive wire and tapped the light to the terminal on the battery. How do I do that test and what will I need please,
 

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To do a battery drain test you need to disconnect the negative battery terminal and connect your multimeter in series between your battery and the battery cable. You need to latch over or shut all doors and lock the vehicle. You'll need to research BMW specs for maxium current draw, ford say 0.05amps max, but under 0.1 should be ok. If its more than that you need to pull the fuses one at a time until the current draw drops below 0.1 amps.
 

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And you shouldn't test a starter with a test light, you should use a multimeter. Just because the test light has illuminated, it doesn't mean that you have 12 volts there.
 

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Discussion Starter #8
I test the battery, to prove that something is draining the battery.
I also did change the starter and pulled all fuses and it's still pulling 12 volts? What could be pulling voltage while the power is off besides the starter?
 

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You know the car doesn't go to sleep for 18 mins. after shutdown, right?

Also, I think the guy above was saying that maybe you're not measuring the drain, but only the battery's voltage.

Also, had you checked to see that your alt was charging correctly. When my battery was very low, I also got just a click. It may be that also with your driving habits, that the battery never was fully charged. If you make a lot of short trips, you'll drain more than charge, since starting pulls a huge amount of power.
 

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Discussion Starter #10
Yeah I get it, let me explain more.
I thought it was my battery cause it didn't have enough voltage to turn the starter. I changed the battery and it drained the second one too... So this is what's happening. Whenever I check the terminal if it's pulling voltage it is. So what could be draining the battery when the car is off... And please help me dmax I know you know a lot about BMW's
 

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First, sorry, have you tried jump starting the car?

Check connection everywhere...beginning with the + terminal. Look for looseness and corrosion....keep going around to major grounds.

If it jump starts, it could be as I said...you're not driving it long enough, often enough. Use cluster test to check voltage when the car is on.

FSR, as I said, will drain the battery...but so will starting the car with too little driving.

Even if the trunk lights and glovebox light were on, it wouldn't be drawing a lot of current. Also, I don't know a lot about electricity, but you're concerned about voltage...any drain, afaik, big or little, will be 12V. You're concerned with amps...and the car when shut down draws a minor current...I don't know the number off hand, but very little.

What is your typical drive like during the week? 5 miles, shut down, then 5 miles back home? You happen to have a friend with a charger?
 

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Discussion Starter #12
No I actually drive daily like 20 minutes and it starts with a jump start but the weird thing is. When I try to start it and it clicks, I just tap on the battery terminals + and - with a socket wrench and it starts right up
 

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Ah...okay.

New battery...so maybe dirty terminals or the clamps aren't really tight on the battery. You've tightened them, but they might not be tight. Try pulling up on them and seeing if they're tight. If not, they make a spacer for that. Clean the terminals and inside the clamps for corrosion.

Check the ground strap...again for tightness and corrosion...scrub with wire brush.
 

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+1 Sound like a battery terminal issue.

And there are various current draws still after 18 mins- alarm, radio/clock memory etc. they should be very low unless there is an issue.
 

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Discussion Starter #15
They are tight but they might be corroded a bit, they have a little white corrosion but could this cause the problem of draining the battery? Also what is fsb?
 
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