[Logger]

Vehicle "goes to sleep" is the best way I can sum up my problem but let me explain in detail...

This seems to be an intermittent problem - sometimes when I open the driver's door while the vehicle is off, I have no interior lights and pressing the rear hatch release or door unlock button, nothing happens. Almost like the battery rundown protection has kicked in. But what's strange is this can happen within a couple minutes of shutting off the engine. A couple of examples of what I'm noticing:

1.) I'll park in the garage, open the door and get out, close the door (interior lights go off after a couple of seconds). I come back in a minute or two, open the door and no interior lights, hatch release button doesn't work, and power door unlock button doesn't work. Pressing a button on the keyfob (hatch release or door unlock) wakes the vehicle up!

2.) Park the vehicle, open the door, hit the lock button, all interior lights extinguish immediately while the door is open (and now cannot open the hatch with the inside button or unlock the doors with the power door unlock button).

3.) After driving then shutting off the engine, open the driver's door and the radio does not shut off or interior lights illuminate. Opening and closing the door several times does nothing, have to open the passenger door to shut off the radio. (NOTE: this is rare but does happen occasionally)

At first I was thinking a bad door switch on the driver's door; the vehicle wasn't seeing the driver's door as "open". But doesn't explain, to me, why the battery rundown seems to kick in within a minute or two like in example #1 above or why the vehicle goes to sleep immediately like in example #2. And again, these problems are intermittent - I'll walk out there right now and everything is fine. Two minutes later, I've got a problem. Any thoughts on what the issue here is?

Another odd electrical behavior I've noticed is right when I start the vehicle, the voltage gauge is a little low on voltage for about 3 seconds then kicks up to a "normal" voltage - don't know if this is related or not.

 

[GaryDoug]

Hi Charles,

This seems to me like a problem with the body control module (BCM) or one of the power or ground connections to it. It could hep a lot if you could measure the voltage at the BCM connector sockets while the problem occurs. The connectors can be accessed by removing the lower IP panel on the passenger side. If you can attempt that, I may be able to guide you through it.

Otherwise, check the fusible link from the BCM power wire located between the two fuse boxes under the hood. Another possibility is the ignition switch.

 

[ZumpTA]

My volt gauge always hangs low for about 3 seconds after turning key to "run". I never start my engine right away. I always give it that couple seconds to let the fuel pump prime, and I suspect that's all it is, the fuel pump placing a load on the electrical when the engine is not running. I have always assumed this to be normal behavior. The rest of it though, zero idea, GaryDoug's the man for that. No BCM in my vehicle to gain experience with, but from what I hear of it, it does sound likely. Good luck!

 

[Logger]

Hi Charles,

This seems to me like a problem with the body control module (BCM) or one of the power or ground connections to it. It could hep a lot if you could measure the voltage at the BCM connector sockets while the problem occurs. The connectors can be accessed by removing the lower IP panel on the passenger side. If you can attempt that, I may be able to guide you through it.

Otherwise, check the fusible link from the BCM power wire located between the two fuse boxes under the hood. Another possibility is the ignition switch.

Ah, BCM... I was afraid it might be that! I was really hoping for a bad door switch because I was planning on tearing into the doors this summer anyway to replace the speakers. I'll get into the area that the BCM is located hopefully tomorrow afternoon and get back to you. But I did look under the hood and found the fusible links you pointed out but there looks like three of them. Which one would be for the BCM? And what do I need to check - just continuity on the fuses or am I looking for bad connections?

 

[GaryDoug]

This is what I would do: The next time this happens, leave everything as is with the driver side door open. Remove the cover to the fuse panel (or have it already removed) and measure the voltage at each of the following locations referenced to chassis ground: power accy fuse and courtesy fuse. There should be very small holes on the tops of the fuses for access. Measure both ends to make sure you don't have a blown fuse. If you have 12v at each one, switch on the headlights. If they do not come on, the fusible link is bad (although that should not cause this problem) and that is one of the smaller (1.0 sq mm black) two that are tied together at the terminal post. If there is no 12v at the power accy fuse, same thing. If the courtesy fuse has no voltage, the problem is with the fusible link that is by itself at the post. It should be larger in diameter (2.0 sq mm gray) than the other two. If you have 12v at both fuses and the headlights work, the fusible links are not the problem

Keep in mind that the fusible links are just a few of the many possible faults.

 

[Logger]

Unfortunately, the problem has yet to repeat itself except for once when I was leaving for work (and didn't have time to check things). And I've gone out there at random times just to see if it's acting up! But next time it happens, I'll check those fuses and post back up here what I find.

 

[Logger]

Ok, so an update - I did finally catch the the vehicle doing this over the weekend, twice to be exact. Checked both fuses and both had 12V on them. The headlights also turn on just fine. So no issues there. But of course everything else not working. I did notice I can LOCK the doors but cannot UNLOCK the doors with the power lock switch on the door.

I did also locate the BCM. I'm assuming it's not really "user servicible" but is there anything there I should check?