HUGE battery voltage drop right before my eyes!

[Junior28]

I went out to the car to see where my battery voltage was (as I'm still dealing with a mystery battery drain). I connect my multimeter to the battery and it was sitting around 11.4xx volts with the door open and the interior lights on. I then close the door and wait for the lights to go out but they never did. It's usually about 30 seconds before they go out, but this time they stayed on. I had locked the rear passenger door (not sure why) so I went to unlock it using the button on the front passenger door. The doors unlocked in a "sluggish" way so I did it a couple more times, and they stopped locking/unlocking altogether. I tried the other lock/unlock button on the driver side and again, nothing. So I go back and look at my multimeter and the battery begins to drop from the aforementioned 11.xxx volts. The interior lights began to get real dim as the voltage went all the way down to 4.xxx volts in about a minute! Shocked, I just stood there for a while. Then I hear the instrument panel make the 'engaging' noise (as it does when connecting the battery) and the battery jumps back up to 6.xxx volts. At this point the lights are completely off and obviously the locks don't work with such low voltage.

I'm wondering if this has anything to do with RAP? Looking at this post, (http://www.pontiacbonnevilleclub.com/fo ... 25835.html) would anyone suggest that my problems (battery drain especially) may be coming from a faulty RIM (my guess), IPM, or DIM? I know where the RIM is located, but where are the other two and what do they look like? Also, where is the RAP module and what does it look like?

[RJolly87]

I would check the battery and connections myself. Any healthy battery should be able to provide loads so great that it can blow wiring just about anywhere in the car.

11.4 volts isn't a good place to start with either.

[Junior28]

The battery is good. It was at 11.4v because it was connected for a couple days already before this happened. It started out at 12.5v when it was fully charged. This slow drain has been the case in at least 3 batteries I've had in the Bonne from other cars.

I'm just not sure what caused this huge sudden drain though...

[bobgto65]

Have you taken the battery to have it load tested? A bad battery can read 12V but will drop quickly under small loads.

[RJolly87]

If the battery is good, it is likely dead and can't support the load being put on it with the current charge.

Usually the best way to handle a parasitic drain like you describe is to connect an ammeter in line with the battery, and watch the amount of amps being pulled. It should fall within a certain range. If it is above, you attempt to isolate the source by pulling fuses until the draw drops. There is a bit more to this procedure, but that is the jist of it.

[1oldman]

The remote is not going to work properly with low voltage from the battery. I speak from personal experience. The voltage needs to be above 12 or 12.5vDC before the remote will function properly. Pull as many fuses as you can easily get to making sure you know where each fuse goes back (including the correct AMP), put a full charge on the battery, then see if there is still a power drain on the battery. If you still have a power drain, start pulling the hard to reach fuses until you lose the drain. If not, put the fuses back one at a time until you find the power drain. Use your DVOM to look for the drain. - BC

[Junior28]

Thank you all for the replies.

I pulled this current battery out of another vehicle. We had just gotten the battery less than a month ago and it was completely fine in the other vehicle which is why I am hesitant to believe that the battery is at fault. I pulled each fuse/relay/wharever-else under the back seat and none of them caused a drop in how much power was being pulled. With all the fuses connected, as soon as I set my multimeter to check for a parasitic draw (and connect the leads accordingly) the draw is at about 1.6xx amps. Then after maybe a minute, it'll drop to 0.160 amps,then maybe another minute later, I'll hear a "click" and it'll drop to 0.033, then a couple seconds later it will finally drop to 0.007 or 0.008 amps where it will stay for the few minutes I stare at it...

I went through this process multiple times as I tried to figure out which relay the "click" was coming from. If I remember correctly, if was the RAP relay. Swapping the relay for a spare did nothing at all.

At one point, just for kicks, I disconnected the whole fuse box from the positive cable that comes from the battery cable and my multimeter read ZERO parasitic draw (for what it's worth...)

What seems to be happening to me is that something in the car turns back on many minutes (hours maybe?) after the parasitic draw drops to .007/.008 amps (which is a normal draw, right?).