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2004 SUBURBAN PARASITIC BATTERY DRAIN DRAW BCM? Have PICS & VIDEO OF PROBLEM... CANT FIGURE THIS ONE OUT!By W8MCC
2004 SUBURBAN Z71
I need some help.
My suburban sometimes goes dead. It will go dead every day for a week, and then not again for a month. Right now, its doing it again.
Replaced the battery (twice) on a new battery < 1 week old.
Had the alternator tested 3 times.
Replaced a questionable looking harness connection on the alternator with a soldered in connector properly heat shrunk.
Replaced the Instrument cluster about 6 months ago with a rebuild due to bad steppers. (not because of battery drain) but I mention it because its popped up before.
Performed numerous parasitic draw tests and found a possible issue:
Here's what I have found so far. My natural battery off state is 0.03A or 30mA. I have confirmed this with a matching truck I have where it has an off state draw of 22mA. They're within reason to each other so I consider that the normal state for my vehicle.
I have caught what I feel to be the issue twice, where I have a draw of 0.22A or 220mA almost a 1/4 amp and solid. It doesn't happen every time though. I only luckily found this twice while testing. The only way I can get the draw to disappear when it comes up by itself is to pull TBC BATT. And I only know its happening because I have a meter in line with the battery while testing.
I can simulate this same draw by doing the following:
1: Wait for the natural off state to settle in around 0.03A. This takes about a minute, first it starts off at 2.8A, then drops to 1.8, and so on as features are put to sleep after connecting the battery.
2: Pull the LBEC 1 Fuse. This makes the battery draw jump from the settled state of 30mA up to 190mA.
3: Reinsert LBEC 1 Fuse. This then jumps the battery draw all the way up to 220mA, which I consider to be the actual problem. The thing is it never drops back down. It just sits there indefinitely.
4: (to solve the issue) If I pull TBC BATT that instantly drops the draw back to the normal off state current, and when I reinsert TBC BATT the draw doesn't come back until I repeat the process above.
A: when this happens, pulling any fuses in the cabin fuse panel does not drop the current.
B: There is an audible click from a relay or something INSIDE the BCM under the dash. My other truck does this too, but I'm not sure what's on the aft side of that connection.
I checked out some of the free wiring diagrams at autozone. Unfortunately they're not organized too well and I'm getting lost with them, that and once the diagram enters the BCM I'm not sure whats going on with the circuits after that.
Anyone here have some insight to what to do? Like I said before, I have another identical truck (just not Z71) I can swap parts and pieces with to narrow it down. I will mention that on the other truck, if I do the steps above I get the same result BUT it eventually does settle down to 0.02A by itself where the Z71 does not. It just draws that 1/4 amp all day long (usually all night long).
Here's a video of my test:
Here are the two offending circuits in the underhood fuse panel:
My 2015 Silverado 1500 4x4 crew cab has about 110000 miles on it. It just started having an issue that I cannot seem to fix. The engine stays running when I turn the key to the off position and remove it. The accessories turn off normally and the RAP seems to be working. Meaning the radio and things turn off when I open the door....this truck is all stuck with the exception of a light bar. I’ve already pulled the light bar fuse at the battery hookup to see if that had anything to do with it and it made no change. Any ideas? Thanks
I hate to start a new topic but looks like I had to,
So I'm doing an escalade interior swap on my 2008 chevrolet silverado 1500, I got a full donar vehicle, what I will do is pull the whole dash, counsel, seats, and all the interior wiring, but use my silverados bcm, one issue that I am facing is how will I add the vci numbers for the seats and pretty much the whole dash to work with my 2008 silverados bcm since it never came with all those features,
Gm in Canada here is to stubborn to create vci numbers and they simply won't do it,
Is there any advice I could have?
Can gm program the bcm without the truck being at the dealer?
By Chris Lara
I noticed that there have been several posts a on the Hyperflash problems with LED tail lights. I've got a 2015 that I updated to Axial tail lights and they worked great for about 2 years. Recently the passenger has been hyper-flashing about 90% of the time. The light works fine, so it's not really out. I put the stock lights back in and they are fine. Any thoughts on how to repair the light and/or figure out what resistor needs to be replaced?
Thanks in advance for input and I'd appreciate any advice.
I am currently sitting in front of boost autos High beam to spot mirror mod for the 2019+ HD trucks. This kit taps into the BCM using a relay and a diode to achieve the spot lights on while in drive. I'll attach a install link that shows the wire taps in the BCM. Although this kit sounds nice, I don't want my Task lights (spot lights) on whenever my high beams are on, but rather have the option to use the stock dash button to achieve my desired lighting while in drive. From what I've broke down I believe this to be a ground activated relay and could be done differently then tapping into the high beams. The kits relay is wired as follows: 30- red to fuse with a jumper to 30, 86-black, 85- red jumper from 30, 87- dual outputs with diode. Could anyone simplify this for me to where I can either just always have use of my mirror lights in drive or park, or what I need to wire/jump etc to achieve this? I feel like I'm over thinking this and there should be a simple answer that tricks the truck's mirror lights to believe they are still in park. Maybe a ground wire just tapped in or something???
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