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Large Parasitic draw


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proteus999
New User

Mar 26, 2019, 1:34 PM

Post #1 of 5 (1784 views)
Large Parasitic draw Sign In

I have a 2013 chevy express. I have had this problem for 2 years!
for the draw test I have 3.7amp draw. I have disconnected both fuse boxes, starter, alternator. with all these components disconnected, I still have a 3.7amp draw. Battery is dead over night. This problem is it's also intermittent. So I disconnect the battery every nightMad Where or how do I detect the short?
Dave


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 26, 2019, 3:21 PM

Post #2 of 5 (1781 views)
Re: Large Parasitic draw Sign In

You're probably not checking it correctly.


There is a procedure for finding a battery draw like that.

You will need a digital ammeter and a jumper wire with clips on the ends to do this.
First rig any door switches so you can have a door open without triggering the interior lights and unplug the hood light. Remove one battery cable and attach the meter in series between the battery cable and battery post. Take the jumper wire and also attach it the same way. Leave the jumper wire on for at least 30 to 40 minutes to expire all the automatic timers. Now remove the jumper wire and read the meter. Anything over 50ma is too much draw. The way you locate this is to start removing fuses one at a time until the meter drops to normal level. This will be the circuit with something staying on. Determine what components are part of that circuit and check them individually until the problem is isolated.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



proteus999
New User

Mar 27, 2019, 1:25 AM

Post #3 of 5 (1762 views)
Re: Large Parasitic draw Sign In

That is what I did, fluke digital meter and alligator clips, only instead of pulling fuses. I disconnected the battery power to the entire fuse box. Drain is still there .The only other non fused circuits are the starter and alternator which I also disconnected the positive power wire going to them. so there is no power, to any circuits connected to the battery, still 3.7 amp drain with nothing connected to the battery.
I am assuming I have an intermittent short? But don't know how to trace it.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 27, 2019, 3:43 AM

Post #4 of 5 (1760 views)
Re: Large Parasitic draw Sign In

? Are you sure it's a 3.7 AMP draw? That a lot! Would take down a battery in little time not just overnight. How many time has this battery gone dead since this did this? Battery itself can't take being DEAD and recover sometimes just once if lucky a few times.
I'm only lost right now that it works to disconnect it unless rare you may be putting a charge on it are working with a super weak almost ruined battery.
Anytime it's compromised or delivers lower power then a higher use item needs like motors of any kind, relays etc. Those can get almost glowing hot and stick on. That ruins that item right away or eventually. For that back to the fuse pulling test for what wire or item then don't trust battery if it's gone deal it's not like a cell phone type that can - know that,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 27, 2019, 4:50 AM

Post #5 of 5 (1756 views)
Re: Large Parasitic draw Sign In

No, you are not doing it correctly. You do not disconnect entire fuse boxes. You are not allowing modules to go to sleep. That kind of draw should be very obvious somewhere. That would be a complete set of lights staying on or a motor running somewhere.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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