Troubleshooting Parasitic Draw - Page 2 - Defender Source
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  #21  
Old August 22nd, 2014, 04:11 PM
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Quote:
Originally Posted by founD90 View Post
At no point can I get the truck to measure the 14.5V I read it should with the truck running. Does this point to the alternator as my fault?
Does your alternator have an exciter wire that is being connected even though the truck is off? Is the exciter wire disconnected altogether?

Did you do any wiring "mods" recently?
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  #22  
Old August 22nd, 2014, 04:51 PM
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Quote:
Originally Posted by sonoronos View Post
Does your alternator have an exciter wire that is being connected even though the truck is off? Is the exciter wire disconnected altogether?

Did you do any wiring "mods" recently?
No mods at all, totally stock. I haven't touched the alternator since I reinstalled it last Fall but all the wires are in their proper location. Bear in mind, up until last Friday's road trip everything worked just fine.

To the earlier questions:

1. With alternator disconnected, I still have the phantom draw
2. Yes, the alternator get's rather hot quickly.

Still not seeing 14.5V when it's running.
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  #23  
Old August 22nd, 2014, 04:53 PM
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Then I concur with the theory that the alternator is dead/dying.

You could double check by checking charging current while the engine is running (the same way you measured discharge current).
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  #24  
Old August 22nd, 2014, 05:05 PM
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Could be the battery itself, even if new. Test it, charge it, disconnect the leads, put the meter on it & let it sit over night to see if it bleeds down on it's own. Checking for an internal short.
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  #25  
Old August 22nd, 2014, 08:29 PM
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Quote:
Originally Posted by transientmechanic View Post
That only tells me that it sees absolutely zero current. That's much different than actually measuring draw at that resolution.
I thought the two zeros to the right of a decimal would be enough to show that a meter and read in the hundredths of a mA. I'll hook it up to a car on Monday and see what it says.
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  #26  
Old August 22nd, 2014, 09:13 PM
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Originally Posted by Jymmiejamz View Post
I thought the two zeros to the right of a decimal would be enough to show that a meter and read in the hundredths of a mA. I'll hook it up to a car on Monday and see what it says.
Current measurements that low are pretty meaningless that low anyway so I wouldn't worry.

Troubleshooting battery drain can be a bitch and has to be done very methodically. A friend once had a 911 that wouldn't hold a charge for more than a few days. He eventually discovered the plug for the drivers side electric seat had a crushed wire that was shorting out. But it took a long time and caused a lot of stress with car failing to start on many occasions.
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  #27  
Old August 22nd, 2014, 09:16 PM
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Quote:
Originally Posted by leastonce View Post
Current measurements that low are pretty meaningless that low anyway so I wouldn't worry.
I agree with that 100%, I'm just saying that a DVOM can read that low.
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  #28  
Old August 23rd, 2014, 03:17 PM
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Took the alternator out, ran up to Autozone for a test.

Failed, Failed, Failed

Alternator is Bad.

So now I have to go back to the place that rebuilt it in November. Hopefully this solves the problem

Thanks
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  #29  
Old August 23rd, 2014, 03:31 PM
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Fun fact for draw testing: Your readings will not be accurate if the battery is dead. Obviously I could never have made such a novice mistake such as that
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  #30  
Old August 24th, 2014, 06:58 AM
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Quote:
Originally Posted by founD90 View Post
Took the alternator out, ran up to Autozone for a test.

Failed, Failed, Failed

Alternator is Bad.
Curious if you were able to get readings after it started warming up. I bet you'd see the drop-off once it started getting hot.

Per Jimmy, have your battery checked too at autozone , just in case.
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  #31  
Old August 27th, 2014, 11:02 PM
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Update:

Good:
Alternator had bad regulator. Fixed, reinstalled, and now puts out solid 14.4 volts.
Battery is new, good, tested, charged.

Bad:
Something is still draining my battery. I've pulled every fuse and tested using both a multimeter and a test light...twice. No fuse seems to be contributing to the drain. I've pulled every fuse in the in-cabin fuse box behind the gear shift, and the small one under the hood on the passenger side. Including all the accessible relays in both areas.

Driving me nuts. Any suggestions?
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  #32  
Old August 28th, 2014, 12:43 PM
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Quote:
Originally Posted by founD90 View Post
Update: Good: Alternator had bad regulator. Fixed, reinstalled, and now puts out solid 14.4 volts. Battery is new, good, tested, charged. Bad: Something is still draining my battery. I've pulled every fuse and tested using both a multimeter and a test light...twice. No fuse seems to be contributing to the drain. I've pulled every fuse in the in-cabin fuse box behind the gear shift, and the small one under the hood on the passenger side. Including all the accessible relays in both areas. Driving me nuts. Any suggestions?
winch?
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  #33  
Old August 28th, 2014, 01:05 PM
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I'd have to get into a wiring diagram to help further, if I can find one online I will try to help.
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  #34  
Old August 28th, 2014, 01:13 PM
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How are the connections around the starter?
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  #35  
Old August 28th, 2014, 05:46 PM
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I made some progress, but I'm still running into walls.

Noticed that alternator is making high pitched sound when battery is connected. When I disconnect the power (fat brown cable) to the alternator, sound goes away.

I tested the continuity of all the wires that go to the alternator - they all tested fine.

Took a moment to consider and realized that if the ignition switch was fried, it would leave the connection to the alternation hot all the time, so I decided to disconnect the ignition switch and...nothing happened. Still getting outrageous draw.

The only time the draw disappears is when I pull the brown power wire to the alternator. I tested all the different permutations of brown and red wires, pulled fuses and whatnot.

So my wiring diagram shows that cable going:

Battery ----> Starter -----> Alternator

What could be happening at the starter that would cause the alternator to never shut off?
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  #36  
Old August 28th, 2014, 06:03 PM
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Bad starter solenoid?
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  #37  
Old August 28th, 2014, 06:11 PM
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Quote:
Originally Posted by javelinadave View Post
Bad starter solenoid?
My thoughts are with this as earlier posted. I not sure if you could disconnect the hot to the starter and check for the draw...
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  #38  
Old August 28th, 2014, 06:13 PM
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Yep - time to check the starter. The hunt continues.
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  #39  
Old August 28th, 2014, 06:49 PM
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So while the engine is off, there is a draw that goes away when you disconnect the alternator? How large of a draw? With the information we have so far, it sounds like a bad diode in the alternator. Questionable rebuild by this shop.

------ Follow up post added August 28th, 2014 06:54 PM ------

There is nothing external from the alternator that would cause it to "stay on". Any draw from the main power cable into the alternator is indicative of a failed diode.
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  #40  
Old August 28th, 2014, 11:39 PM
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Adam - I might get myself in trouble with my multimeter readings, but here goes:

With the my DMM set on 15A, the draw registers at about 1.300

Once I disconnect the brown battery line from the alternator that same measurement drops to about 0.008
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