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Current on a car with nothing on?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=79518
Printed Date: May 15, 2025 at 9:38 PM


Topic: Current on a car with nothing on?

Posted By: datspeed77
Subject: Current on a car with nothing on?
Date Posted: June 23, 2006 at 3:14 PM

What's a normal current draw on a car with nothing on?  I have a customer with an Escalade drawing .3 amps of current with nothing on!  Trying to find out if this is normal or not. 



Replies:

Posted By: Custom_Jim
Date Posted: June 23, 2006 at 4:09 PM

With nothing on, normal would be 0.00A  Having 0.3A is a fair amount and I would look to see if anything aftermarket is installed or possibly if there is a factory item on that might not be visible (glove box light, console box light, vanity mirror light) but be on. If all else fails start pulling fuses until the amperage gets down to about 0.02. This amount would be normal for a lot of late models with memory circuits that need to stay powered. Once you find the circuit (like by pulling the fuse out) you need to see what is on that circuit by using a wiring diagram or tracing it out. Some fuses are wired to multiple things and it could be one or multiples that are causing the excessive current draws.

Jim 



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Posted By: luckydevil
Date Posted: June 23, 2006 at 4:40 PM
Not sure, but does ONSTAR work while the car is off?




Posted By: auex
Date Posted: June 24, 2006 at 10:01 AM
I hope you are waiting at least 1/2 hour before measuring the draw. You can't use the measurement when the computers are still on. GM considers anything over 500mA parasitic.

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Posted By: NowYaKnow
Date Posted: June 24, 2006 at 10:22 AM
"What's a normal current draw on a car with nothing on?"

These range depending on year/make/model. The normal draw is somewhere between 20 - 50mA. Your customer with 300mA draw is WAY over the allowable amount.
And there is no need to wait 1/2 hour in most cases you can see the changes in a minute or so, or at least be able to troubleshoot it adequately. And GM probably considers anything over 50ma parasitic, not 500mA - that's WAY high.

First thing to do is check every cig lighter in the vehicle to make sure they have nothing plugged in since most cig lighters stay on nowadays. I've fixed many amp draw problems just by showing them to unplug their incense or whatever the hell else they plug in and never remove.

Next step is to close all the doors and make sure all the lights go off - including any lights in the glovebox,consoles, underhood etc.

After that rule out any of your aftermarket equipment that you may have put in by unplugging the modules or disconnecting the wiring completely.

If it still has a draw, your next option is to watch the meter and start pulling fuses from the fusebox one by one. At some point your draw will drop and from there you can find out what is on that circuit (owners manual) and trouble shoot.

This is the method I use and can usually completely troubleshoot a problem in about a half hour. Or at least be able to narrow it down far enough to get the customer/dealer off my back and let them fix their end of it.

Good luck,

Mike





Posted By: datspeed77
Date Posted: June 24, 2006 at 7:58 PM
Thanks for the info guys, i found a relay stuck on the on position.  Changed it out and read .025 amps.  Just to let you guys know, you do have to wait 20 minutes before checking on the Escalade.  The car read .2 amps for about 20 minutes then dropped down to .025 amps. 




Posted By: x-performance
Date Posted: June 25, 2006 at 3:08 AM
what tool are you guys using to measure the current draw?




Posted By: geepherder
Date Posted: June 25, 2006 at 7:19 PM

If you're measuring a large current draw, use a clamp on meter.  For small measurements, use a regular old dmm.



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