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a1parrothead
New User
Feb 4, 2016, 11:24 AM
Post #1 of 6
(1603 views)
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Parasitic amp draw
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I need help. My 2007 Chevy express van has an amp draw that is really confusing me. I will start off by saying I think it may be in the ignition, but let me explain. Its odd. I take off the negative battery cable and use my amp meter in line between the battery terminal and cable to watch the amp draw. I get a reading of .58 amps. It will stay like that FOREVER. I mean until the battery is dead. But…… I pull the radio fuse and the amp draw drops off to zero. I do not have the factory radio in. Actually I have in an aftermarket navigation screen/dvd/radio all-in-one. I put the fuse back in and the draw goes back to .58 amps, BUT….. then drops off to zero again. Every time I reconnect the battery, I get that CONSTANT .58 draw that never ends until my battery is dead. Only by pulling the fuse and putting it back in can I get the amp draw to drop and end. But every time I start the cycle over the amp draw comes back and will not drop off on its own until after I pull the fuse and put it back in. Very strange. I also have an intermittent door chime that rigs telling me my keys in the ignition, except that my key is not in the ignition. That is what makes me think that all of this may have something to do with my ignition switch. Any help would be greatly appreciated. I know that there will be an initial amp draw from the Control Module and from things like the radios/navigation's memory. The confusing part is the weird pattern of the amp draw. Why does it drop off sometimes, and then stay on forever at other times? Jeff
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Discretesignals
Ultimate Carjunky
/ Moderator
Feb 4, 2016, 6:07 PM
Post #2 of 6
(1591 views)
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Re: Parasitic amp draw
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I'd say it would have to do something with your aftermarket radio. The original radio had constant power from the RDO fuse and would communicate on the data bus with other modules including the BCM that would control the retained accessory power function.
Did this problem start after you installed your aftermarket radio?
Does this have a chime module, or does it chime through the radio speakers?
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Feb 4, 2016, 6:15 PM)
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a1parrothead
New User
Feb 4, 2016, 6:43 PM
Post #3 of 6
(1588 views)
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Re: Parasitic amp draw
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The source of the parasitic amp draw is not the thing that confuses me the most. It’s the fact that if I pull the fuse and put it back in, the draw will appear, but soon drop to zero. THEN, if I disconnect and reconnect the battery, the amp draw will be present forever. Or at least until I pull the fuse, put it back in, the draw appears, but then drops off and is gone again. It’s a vicious cycle. The only way I can be sure the amp draw is disappearing is to pull the fuse and put it back in again. That is the only way I can be sure the amp draw will ever drop, other than pulling the fuse and leaving it out. But if I mess with the battery cables (connect/disconnect) then that amp draw will stay until I pull that fuse and put it back in. What is going on? Jeff
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a1parrothead
New User
Feb 4, 2016, 6:44 PM
Post #4 of 6
(1587 views)
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Re: Parasitic amp draw
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I am not so sure about the chime. I will check.
Jeff
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 4, 2016, 11:52 PM
Post #5 of 6
(1581 views)
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Re: Parasitic amp draw
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Just some comments/thoughts: Drain should be low but never ZERO. When you attach a battery cable drain should be up for a limited time then rest.
Chime? If this aftermarket device has used a wire associated with key or lighting on and chimes away it fooled that feature to thinking the key is still present or the lock cylinder not right?
Hey - you say you are finding battery dead and there's only so long that game is going to last before battery is junk and put out wrong voltages and fool things and give improper info or lack of info you want.
Aftermarket devices if not installed with vehicle specific exact diagrams or adaptors are responsible for many if not most of bizarre problems like this,
T
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nickwarner
Veteran
/ Moderator
Feb 6, 2016, 1:38 AM
Post #6 of 6
(1555 views)
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Re: Parasitic amp draw
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Redo your test with the radio unplugged at the harness. Leaning toward the aftermarket unit misbehaving
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