Battery Drain 2000 Bravada

Reply

  #1  
Old 11-25-11, 06:32 PM
Member
Thread Starter
Join Date: Aug 2006
Location: iowa
Posts: 52
Battery Drain 2000 Bravada

I have a 2000 Bravada that is draining the battery while setting. Very difficult time locating the source of the drain. With an amp meter I have measured and pulled fuses one at a time to look for the drain, no definite source. I have replaced the body control modual and went without courtesy for a couple of weeks with no change to what is happening. Looking for suggestions on where to turn next.

Thanks,
 
Sponsored Links
  #2  
Old 11-25-11, 07:18 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,191
I am not doubting you did it right, but just in case:

Remove the negative side battery cable from the negative battery terminal.

2
Connect the black wire to the com input on the multimeter and the red wire to the 10A or 20A input on the multimeter. the meter needs to be able to read at least a 2 or 3 amps for this test to work. Connecting the red wire to the mA input on the multimeter won't work and could damage the meter.
3
Attach a multimeter(set the dial on the multimeter to measure Amps as per multimeters instructions) between the negative cable and the negative battery post. Wait a few seconds to several minutes for the car to go into sleep mode - i.e. when you make the contact with the ammeter, the cars computer systems "wake up". After a bit of time they will go back to "sleep".
4
If the ammeter is reading over 25-50 milliamps, something is using too much battery power.
5
Go to the fuse panel(s) and remove fuses, one at a time. Pull the main fuses (higher amp ratings)last. Perform the same steps for relays found in the fuse panel. Sometimes relay contacts can fail to release causing a drain. Be sure to observe the ammeter after pulling each fuse or relay.
6
Watch for the ammeter to drop to acceptable drain. The fuse that reduces the drain is the draw. Consult the owners' manual or service manual to find what circuits are on that fuse.
7
Check each device (circuit) on that fuse. Stop each lamp, heater, etc. to find the drain.
8
Repeat steps 1&2 to test your repair. The ammeter will tell you exact numbers.
 
  #3  
Old 11-25-11, 07:58 PM
Member
Thread Starter
Join Date: Aug 2006
Location: iowa
Posts: 52
Thanks for the input I will try this. I was looking at the hot line and not the neg line. I was also using an induction meter at the time along with the other meter.

What is an acceptable draw?

Thanks,
 
  #4  
Old 11-27-11, 08:01 AM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,191
don't know. you have some vital devices that run continuously, like ECM, or clock, stereo presets are backed up. I'd prolly safely say, if you see any substantial drop in power draw, you got your culprit.
I've heard some use 12V bulb in line with negative, and when it turns off, that's the fuse.
oh, and stop replacing parts on guess, please. really not healthy for your wallet.
 
  #5  
Old 11-27-11, 10:27 AM
Member
Join Date: Mar 2009
Location: Texas
Posts: 1,051
One thing I did not pick up on so far was your confirmation that your battery was capable still of holding a solid charge. I am guessing that if not recently replaced this maybe only the second battery in the truck and it is now time also. What testing have you done on this, or is there already a new battery installed also?
 
  #6  
Old 11-27-11, 11:13 AM
Shadeladie's Avatar
Super Moderator
Join Date: Jan 2005
Location: USA
Posts: 3,796
Not that I know anything about cars but the same thing was happening to my husband's truck a couple months ago.
Does your car happen to have a light under the hood? Turns out that light wasn't going out when the hood closed. Not that it's your problem, but thought I'd throw it out there just in case.
 
  #7  
Old 11-27-11, 11:41 AM
Member
Thread Starter
Join Date: Aug 2006
Location: iowa
Posts: 52
Thanks for the input. The battery is less then 1 year old and has been tested 3 times. the only reason I replaced the BCM was it was identified during my first round of testing as having the greatest impact, not sure what all that controls. The hood light is a good suggestion but not it in this case I have disconnected it early on. Thanks for the idea.

I have noticed in the last couple of days even starting it right after running it sometimes cracks hard, sounds like it is working at turning over and then pops off and starts.

I still have not had the opportunity to retest, but will do that.

Thanks again for the help.
 
  #8  
Old 11-27-11, 01:47 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,191
BCM is body control module.

The first beginnings of automotive networks began in the Cadillac and Oldsmobile models of the early eighties with the advent of a second computer other than the central engine control module. This new computer had a microprocessor and was called the BCM (Body Control Module). The engine control module (ECM) would control all
engine functions while the BCM controlled items such as automatic lighting, HVAC (heating and air conditioning) controls and alarm and lock functions. The BCM came about as consumer demands and competition led to newer creature comforts in the
modern automobile. GM needed to get a method to tie these two computers together.
http://tomboynton.com/GMnetworks.pdf

hmmmm... ignition lock? considering stumbling starts? you still need to do test right..
 
  #9  
Old 11-27-11, 02:00 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,191
A retrospective from that article. What are we here, poor minded and uneducated, even trying to accomplish with our guesses?

Because of this increased complexity and the fact that wages for automotive technicians (can’t call them mechanics anymore) haven’t increased in proportion to the technology, there is a real shortage of
people willing to fix these complex systems. Working for GM for the last 15 years I have watched all these systems evolve from the simple systems that were around in the eighties to the ridiculously complex systems nowadays. I think sometimes of the vulnerability of some of these vehicles to outside influences. An intense solar flare could
potentially cause millions of vehicles to simply stop working as they are so dependent on computer technology. I’m not quite sure what the future holds for the auto industry, perhaps soon we will see robots working on our cars, I know the technician base is
rapidly dwindling and the new technicians not necessarily seeing a big incentive to join it’s ranks. I, myself, am getting my college degree to find some more respectable work that gets a little more recognition along with a better paycheck. Only time will tell.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'