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Discussion Starter #1
Let me ask you fellas something. I’ve got a 2000 Excursoin 7.3 . I had my trailer hooked up to it for about a week it sat at the house. My batteries are 850 cca Die Hard. They are one year old. Went to start it both were dead. Charged them up both overnight they were fine the next day. Used the excursoin during the weekend parked it with the trailer hooked up. Went out 4 days later wouldn’t start. Charged them up and done a battery test looking for a drain. I was reading 620mv with the door shut and inside lights off. Unplugged the gem module fuse still had the drain. Unhooked my trailer parked it next day I had a 213 mv drain which I think is about normal. Anyone ever had a trailer lights drain a battery or any ideals. I can open the door and the inside lights come on about a 515mv drain lights off 213mv both batteries are reading 12.64 and 12.65 volts any ideals
Thanks Eric
 

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According to the Service Manual, the normal AMP draw (not volts) with everything off and modules "asleep" is 50 mA or less (IIRC).

You need to connect your meter set on amps between the battery post and the removed cable to measure amps. If you depower things by disconnecting both batteries, the modules will "wake up" and likely blow the fuse on your meter. So in order to get it connected, you need to keep one battery connected until the meter is in place, then disconnect that battery.

Then the procedure is to pull the fuses that are the furthest downstream (the ones fed by another fuse) one-by-one while observing the meter. When the amp draw drops below 50 mA, the circuit for the fuse you just pulled is the culprit. Then you have to trace that circuit down to see where the current is going.
 

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Discussion Starter #3
Thanks I had one negative cable unhooked on the drivers side battery with my meter on it. I’ll try it again on Mamps
 

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Discussion Starter #4
I just tested my battery drain. I have a Klein meter that is auto ranging on MIlli Amps with the driver side negative terminal off and the other battery hooked up on the passenger side. With one lead on negative clamp and other on neg post I’m getting a 3.72 MA drain. If I hit the range button on my meter it goes to 3.7 or 0.00 to 0.0 I’m not an electrician as you can tell lol. Any thoughts. Thanks
 

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Everything has to go thru the meter. So if one battery is still connected, you won't be measuring the actual amp draw.


As I said, disconnect one battery cable, connect your meter in series across that disconnected cable, then disconnect the other battery.
 

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Discussion Starter #8
According to my test I am under the 50MA so I should be good. I wonder if something on my trailer was shorting out. I have a 2000 F-350 and a 2000 Excursoin I’m thinking about getting a battery tender for both of them. I don’t drive them all the time.
Thanks for the advice
Eric
 

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That looks like the correct test setup, and you do appear to be under the 50 mA.
If you let them set for months at a time, you may see a slight drain. I don't think I've had mine setting for even a full month.
A battery tender might be a good idea if they aren't driven much.
And you may be right about the battery drain having something to do with the trailer. It should have a relay that disconnects the trailer battery charge feed if the engine isn't running.
 

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Assuming your Excursion has the factory Camper/Trailer wiring and is un-modified a trailer connected when the truck is shut off should not drain the truck batteries. This is due to the fact that the trailer tow battery charge circuit is relay isolated. The relay is energized only when the ignition is in the run position.

Yes, the factory specification for parasitic battery drains id 50 milliamps. To help reduce the chances of blowing the fuses in your multi-meter when performing an amp draw test is to use the "amp" connection which usually has a 10 amp fuse. you can adjust the range on most decent meters if you have trouble with decimal points... The milliamp connection typically has about a 1 amp to 3 amp fuse from the various meter I have seen and they blow eassssssily!
 

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To really confirm your reading, we need to see how the leads are connected to the meter, and the dial setting.
 

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To help reduce the chances of blowing the fuses in your multi-meter when performing an amp draw test is to use the "amp" connection which usually has a 10 amp fuse. you can adjust the range on most decent meters if you have trouble with decimal points... The milliamp connection typically has about a 1 amp to 3 amp fuse from the various meter I have seen and they blow eassssssily!
Also remember to change the leads to the correct position on the meter before trying to measure voltage. That blows the fuse (even the 10 amp one) in a heartbeat. Don't ask how I know that. :winking:
The dang fuses are EXPENSIVE, too.
 

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My ‘99 behaves same. Thought it was the trailer somehow draining but finally ruled that out. Only way I can prevent the batteries draining is to disconnect them.
How are you checking for current drain? Are you individually pulling each fuse in the box? I thought anything over 50mv loss could be draining batteries if not driven regularly.
My back up lights stopped working and I suspect their is a short some where in that harness.
 

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Good chance your trailer plug is always hot. See if you are getting 12 Volts to the plug when the key is off. Buddy had a trailer that kept draining the battery because he had a inverter that was hooked to the fridge. Look for a extra wire coming of the positive side of either battery and trace it out. Relay could be stuck closed (I have not seen that, but could happen I guess). I had a 99 F350 that did not come with the factory relay plug/ harness. The previous owner just ran a hot wire from battery to trailer plug.
DENNY
 

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Following along with your suggestions on my ‘99 F250 7.3 trying to determine current drain.
Both batteries disconnected, Fluke set to 300mA scale. Connect meter across + terminal of battery to battery cable. Meter OL. Pull fuse #8 in power distribution box then drain shows 299 mA. The owners guide shows that fuse as Diesel alternator.
?? Where to now.
 

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Well the more I work on this truck . The more bad numbers I get so you can probably disregard my previous message above. Here’s a picture of the meter. Bulk lead to cable+ and red to + post.
Readings: .79 mA and when I pull fuse #6 in PDB it reads .38mA
 

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Well the more I work on this truck . The more bad numbers I get so you can probably disregard my previous message above. Here’s a picture of the meter. Bulk lead to cable+ and red to + post.
Readings: .79 mA and when I pull fuse #6 in PDB it reads .38mA

Your meter in the picture is set to amps and is displaying 790mA. 50mA on your meter will read 0.050 in the 10 amp scale.

Also, be sure that you are waiting the requisite 40 minutes after shutting down the truck and breaking any connections to the battery. Not all modules shut down immediately and most notably the battery saver feature in the GEM module / Central Junction Box in your 2000 Excursion. For some perspective note that "generally" a module will draw ~10mA and an incandescent bulb such as a glove box light may draw ~1A. It is also possible (read that as I have discovered this several times over the years) that a harness concern where water has leeched into a poorly sealed splice or a chafed wire that has dirt and moisture at the point where the circuit insulation is worn off CAN create a parasitic drain as these example can leech power.

Lastly, if you suspect a drain is coming from the alternator, the proper way to discern that is to disconnect both the battery cable and the harness connector on the alternator and retest.






!
 
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