Battery drain
Thread Starter
Racer
Joined: Aug 1999
Posts: 355
Likes: 14
But 80ma is not excessive compared to 25ma! None of the items listed will add only 50ma or so. So, is 80ma too much and if so, what can add such a little amount?
Maybe the one of the modules: BCM, ECM, EBCM?
Maybe the one of the modules: BCM, ECM, EBCM?
Drifting
Joined: Jun 2013
Posts: 1,957
Likes: 342
From: Shell Point (Crawfordville) Florida
By "battery drain" you are talking a current draw, here measured in milliamps. A voltage drop is a totally separate phenomenon related to dirty connections, wire resistance, many other factors, where the voltage may drop from one end of the circuit to another..
Thread Starter
Racer
Joined: Aug 1999
Posts: 355
Likes: 14
sorry, was a brain fart typo, obviously we are talking amps here (milliamps).
And, I do know the difference.
The 80ma did not drain the battery in over 1 week so I'm not real sure it is a problem.
I am testing for the BCM not waking up...VERY intermittently. Disconnecting battery or removing BCM fuse clears problem.
BCM has been replaced 1 year ago. I can't believe that it failed again. Something else must be the cause. There are no codes as a result of the failure.
And, I do know the difference.
The 80ma did not drain the battery in over 1 week so I'm not real sure it is a problem.
I am testing for the BCM not waking up...VERY intermittently. Disconnecting battery or removing BCM fuse clears problem.
BCM has been replaced 1 year ago. I can't believe that it failed again. Something else must be the cause. There are no codes as a result of the failure.
Last edited by y2kvett; Jun 10, 2014 at 06:18 PM.
Drifting
Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
Why don't you follow the advice in post #2 by 8vette7? Your asking for but it reads like your ignoring it. 8vette7 is giving you a good logical approach based on experience and knowledge. He is very familiar with c5 corvettes.
Thread Starter
Racer
Joined: Aug 1999
Posts: 355
Likes: 14
I intend to remove each fuse to see if the drain goes to only 20-25ma. All of the items mentioned as "common" and "excessive" are LOTS more drain than the small drain I'm seeing. And of course, the BCM manages the go to sleep mode. I am pretty knowledgeable about the C5 electronics as well and have fixed bus problems with my oscilloscope. This problem is very intermittent, so am looking/thinking outside the box and trying to investigate things which do not seem normal. Thanks for any advise.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
One thing that can do it is some lighting that does not completely turn off. Seen that before on things like just the HVAC head unit. You can't really tell it in the daytime when you are normally trouble shooting. Get in the car at night and let everything settle down and look around including the trunk. Also, from the outside of the car, don't forget to look under the car and see if the hood light is staying on.
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Thread Starter
Racer
Joined: Aug 1999
Posts: 355
Likes: 14
Well, here is the fix feedback. The BCM was bad again. The replacement now goes to sleep in only 2-3 minutes where the older ones took 15+ minutes. After replacing the BCM I only have 15-16 ma of drain compared to the 80-90ma with the old one. So the darn BCM was causing the drain AND the non-wake up problem. I did remove all of the fuses in the inside Fuse box and the under hood fuse box to test. By removing the power to the inside fuse box (big red cable at under hood box), the drain went away. So I went for a rebuilt BCM and that fixed all the problems.