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Discussion Starter · #1 ·
Ok guys I have been trying to figure out this issue for almost 3 weeks..

During an amp draw test, car acts normal slowly drops amp draw all the way down to 10-30mA which is within spec.

After 45-hour of car sitting fully asleep, something wakes up multiple modules pulling 3.9-4amps! I have confirmed 2A on radio, 1A on AMP, then many other fuses will drop about 0.1A each

Have tested draw with:
radio and amp pulled, pulls the expected 1amp
MSM fuse pulled, no change 4amp draw
Also every fuse in the trunk pulled, will still pull about 0.3A which is 100x spec lol
Cutouts are disconnected, nothing plugged in to USB, wideband disconnected

Now for what I have figured out for sure:
Pulling BCM 1 fuse in engine bay fuse box, will 100% cure the drain issue, left test running overnight a few times with BCM1 fuse pulled, no drain.
Reprogrammed/updated radio with SDS to no avail

So I guess I have questions about BCM 1, it appears to monitor the hood latch sensor (saying hood open no matter what), and turn signals, I haven't found anything else that does not work... when pulling bcm 1 fuse, is it just keeping it out of sleep (and therefore whatever is kicking on is NOT) because it thinks the hood has been opened? Because for the car to be able to sleep and conduct the test, hood and trunk latches must be closed.

I'm sure I have forgotten a few things I've done but trying to keep initial post short so people will read it lol.

Will a bcm from a 2012 work in a 2009? I am going to look at a part out tomorrow
 

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As soon as I read your first few sentences I thought hood latch.

Are you saying your turn signals dont work either?

If your turn signals work and just your hood latch is saying open I would suspect the switch rather than the bcm first. I've replaced 4 or 5 gm hood latches this year, many times they don't get a message on the dash, but the remote start doesn't work. Strange.

Easy way to see if the newer bcm will work would be to check part numbers, see if they were changed or superceded, obviously if you use your car for look up and it supercedes to the newer number it should work, if it's just different all together I doubt it. If it follows most of the changes in the interior I'd suspect only 09 and 10 would work but I'm not sure. All this assuming you have access to something for flashing.
 

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That makes sense that the autostart wouldn't work if the BCM wasn't getting "all locked" from every door/hatch/hood. My wife's previous Acura made you hit the lock button before allowing a remote start. Must be a safety/anti-theft protocol.
 

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Discussion Starter · #5 ·
Ok so there is no ongoing issue with hood latch or turn signals, I was just stating that with bcm 1 fuse unplugged (the only fuse that will kill the amp draw for sure) the hood latch and turn signals are no longer seen.

The car with all fuses plugged in, is 100% fully functional everything works as it should including remote start

BUT it's possible that the hood latch could be failing out after an hour causing something to turn on, but it sort of contradicts the fact that with a hood open signal aka bcm 1 pulled there's no drain, so if it was failing out to open status would it pull amps? Thinking about this just makes me think bcm is bad but all the issues I've seen with amp draw are measured almost instantly, mine is after quite some time
 

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So the way gm sets these up, if you unplug the latch there is no hood open on the dash, but remote start won't work... Have you tried checking for draw with the latch unhooked?
 

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Discussion Starter · #7 ·
No I have not, I was thinking of unhooking it, and testing but wasn't sure about car just not going into the same draining routine, It's just so time consuming as each time I start the test it's minimum 1 hour before testing anything lol
 

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I'm glad you cross posted from the "other" forum. Not much action over there anymore.
 

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Discussion Starter · #9 ·
So the way gm sets these up, if you unplug the latch there is no hood open on the dash, but remote start won't work... Have you tried checking for draw with the latch unhooked?
I unhooked the latch, dash does say hood is open though, so the drain might not be triggered. Testing now
 

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I think you have a damaged wire from that latch that would cause the small draw.
 

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I've seen this problem with a bad door latch switch. Walked to my car and seen the lights and radio was still powered up.
 

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Still drawing a load with the door switch pulled? I'd look for a closed relay AND a shorted positive feed to that switch.
 

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Are you able to remove all loads out of the bcm and see if there's still a draw after some time passes?
 

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Did you hook up a amp meter or remove the negative wire off the battery and put your meter in series with it. You should read voltage. put the fuses one at a time until you loose the voltage. that would be your problem area.
 
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