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Discussion Starter #1
This 02 Focus has developed a battery draining problem that I cannot solve. Back in early May I installed A1Electric keyless entry on this car. It took about 4 weeks because I worked on it part time, and had to install a horn relay and remote trunk relay. So the car sat without being run for better part of a month. But the battery is only about 1 yr. old.

Then about 3 weeks ago I tried to start the car and it was 100% dead--no clicking, no power doors, nothing. I thought maybe a light had been on so didn't worry too much. Then it happened again, and then again, even though the car was being driven. I bought a digital voltmeter on Monday to see if I had a "parasitic" drain problem. Hooked up the 10 amp side of the DVOM in series to the unhooked neg. battery terminal and read 4.7 A (this might be 470 mA?). In any case, this is 3 times the reading I get on my 2005 Focus, which is about 1.2 to 1.4.

So I followed the suggestions from some of the parasitic drain posts that recommended pulling out fuses to see what electrical component is pulling power from the battery. I have pulled out every single fuse in the fusebox and in the engine compartment fusebox and with fuses removed (in groups of 4 to 8) NOTHING CHANGED the parasitic drain reading. Then I pulled the power connector from the A1electric main relay, and connector to the keyless electronic brain box--and with these removed, the result again is NO CHANGE.

I am stumped. the alternator seems fine. Autozone checked both it and the battery on their machine--said they were good. When I run the car for 10 min. the battery pumps up to about 12.4 volts. Then left overnight, it drops down to 11.5 volts or lower. I pulled the neg. battery cable off last night and let car sit overnight like that--and it did not drain down (duh!).

Any ideas on what to try now?
- is there a piece of test equipment that would help?
- battery saver relay be checked or replaced?

Any suggestions that would help isolate this maddening problem would be appreciated. Even something as basic as determining whether the problem is under the hood or in passenger compartment would help.
 

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put a voltmeter on it for about 5 minutes and wait for it to drop a little, and the start pulling fuses. when u pull one and the volts jump back up, u will know in what direction to look in
 

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How many times U check the voltage on the battery?
U maybe just have a bad connecting wiring to the battery to the alternator.
 

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There's a fairly heavy red wire that goes from the alternator to the battery (+) terminal. Disconnect this from the alternator, and see what happens.

Your alternator may have bad diodes. These act like a check valve in a pipe, allowing current to flow from the alternator to the battery but not vice-versa. So if one goes bad (there's usually 3 in there), when you turn the car off the windings in the alternator just sit there and draw current like a stalled electric motor.

This circuit may have a fuseable link, but it has no actual fuse, so that would explain why you have no luck pulling fuses.
 

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Discussion Starter #6
There's a fairly heavy red wire that goes from the alternator to the battery (+) terminal. Disconnect this from the alternator, and see what happens.

Your alternator may have bad diodes. These act like a check valve in a pipe, allowing current to flow from the alternator to the battery but not vice-versa. So if one goes bad (there's usually 3 in there), when you turn the car off the windings in the alternator just sit there and draw current like a stalled electric motor.

This circuit may have a fuseable link, but it has no actual fuse, so that would explain why you have no luck pulling fuses.
Great suggestion. The alternator is charging the battery while driving. Would the alternator still drain battery overnite yet do its job when engine is running (shows my lack of knowledge of alternators!)
I will disconnect this big alternator wire and let you all know what happens.

did you pull the fuse panel loose and check the fuses and relays on the back of it?
Thanx-I did check all fuses in the panel, then pulled the panel to make certain relays were in tightly. But I have not checked the relays--what are U suggesting I do to check the relays??
 

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Not to be an ass, but this is what I would do.

Disconnect the keyless entry system, and see if the problem disappears. IF so, look very closely at what you did, and you could find the problem. If you don't find a problem, then you should contact the manufacturer and get a replacement because something is amiss.

90% of the time when I installed something on a vehicle, and a problem surfaced shortly after- it was a result of what I'd installed. Not that I'm an idiot, or I think you are- but it's human nature to screw up.
 

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Discussion Starter #8
Disconnect the keyless entry system, and see if the problem disappears. IF so, look very closely at what you did, and you could find the problem. If you don't find a problem, then you should contact the manufacturer and get a replacement because something is amiss.
Good suggestion--was exactly what I was thinking right after battery died for a third time. So I did the following: 1. Disconnected the main keyless relay so door motors are out of loop--NO CHANGE. 2. Disconnected horn relay and trunk relay for keyless system--NO CHANGE. 3. Removed the in-line fuse that protects the entire keyless system and powers all 3 relays and the eletronic keyless box--NO CHANGE. I think there is nothing wrong with this keyless entry.

Don't know if I mentioned that I pulled all the large fuses out of the under-hood fusebox and still found NO CHANGE in the drain. This was a big surprise as I assumed yanking those disables the individual component circuits. (I am guessing this--I certainly am a novice on automobile electrics). I plan to test the alternator tonight per the above. -Lytt
 

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Do you have an aftermarket stereo system? If so, you could try pulling any fuse that's NOT located in the fuse box, such as the feed to an Amplifier? If the remote line isn't making contact, your amp could be stuck on, and that'll definately kill your battery.

That's if you have an amp of course :)
 

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Discussion Starter #10
Don't got an amp. I did pull the weird in-line fuse that came with the aftermarket door locks. That didn't change anything. I am really really hoping its the alternator.

(my first car was a 55 Dodge hemi. Car amps are a generational thing :)
 

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Discussion Starter #12
And the answer is (drum roll): THE ALTERNATOR.
Based on BlurvFocus' suggestion yesterday about disconnecting that big red wire on the alternator, that is precisely what I did. Removed that big wire, took my voltmeter/ammeter and measured 0.2A drain when the ammeter connected in series at the positive battery terminal. Reconnected the big red wire to the alternator, and BINGO the ammeter at the positive battery terminal read 5.4A. To make sure I was not dreaming, repeated the whole process one more time and got exactly the same readings. And leaving that big red wire off overnite did prevent the battery from draining.

So after an overly long diagnostic process, I now have the culprit that has been wrecking my battery.
While I would like to save a few dollars by rebuilding this alternator, I shall just go to Autozone and get a rebuilt aftermarket alternator .

Thanks to everyone who came to my rescue on this very perplexing problem--i would not have solved this without your help.
 

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Discussion Starter #13
UPDATE: installed the rebuilt Duralast alternator yesterday (what a royal pain to have to remove all that stuff first!).
Checked the draining problem right away (looks good) and then let the car sit overnight.
Result: no loss of volts.

So the story came to a happy ending. Thanks for listening to my story and puzzling out this mystery.....
 

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Just went through this same situation with my brother's car, except there were a few other symptoms. The car had flickering interior/exterior lights, a rough idle, and a battery draining over night. The battery and the alternator both tested out fine at Autozone. I hooked up the multimeter between the red wire from the alternator and the battery like was talked about in this thread and found it pulling about 4.5 amps when everything was off and closed. After replacing the alternator there were no amps being pulled. Amazing.

Bump - thanks for the good info! [cool]
 
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