Hello,
[first message to this forum - it looks like a wonderful resource!]

I inherited <actually purchased> a '96 Maxima from my Dad. Dad was kind enough to pass along an annoying parasitic battery drain problem, that eventually has fully depleted several Sears Diehards.

With a multimeter and my trusty Haynes Guide in hand, I've been able to determine that when shutoff, the car is drawing 150mA current (Haynes says it should be less than 50mA). Pulling fuse after fuse, I determined that the fuse under the hood marked "BCM" that is the problem. With the BCM fuse removed, the drain is reduced from 150 to just 40mA. Based on info I've been able to locate, the BCM is the Body Control Module.

Now I'm wondering what the next step is to resolve the issue. In general, I'm not sure I have the capability (time, tools, experience) to fix the problem myself, but I'm concerned about paying somebody $90/hr to dink around my car. A couple questions:

1. What devices are on the circuit controlled by the BCM fuse? [based on observation, it appears that at least the automatic door locks and security system are affected]. I could live for a while without auto-locks; if airbags are on this circuit, I'd be very concerned, though.

2. Are there any additional steps I could take to further isolate the root cause of the drain on this circuit - e.g., what BCM circuit devices are easy to detach?

3. Is there a reputable service-repair shop in Brooklyn that can get the job done most cost effectively?

THANKS!

 

I also have a battery drain. When I hooked the battery up to a multimeter, the drain sharply when the BCM fuse is inserted. From reading the manual, its onboard computer which is connected to MANY things. Anyway, it mentions a Sleep mode that it is supposed to enter after 30secs but I was thinking it won't sleep with the hood button open. Have you done anymore tests with the BCM circuit?

 

Anybody know where the BCM fuse is for the 98 Max, and what does the BCM unit look like. Also how do you test the battery for drainage? Thanks

 

I'm at work and don't have my FSM on hand but look in the engine bay, front driver's side. You'll see on the fuse cover BCM. To test the battery for drainage, hook up a multimeter in series with the battery:

1.Unplug positive battery cable.
2.Connect negative cable of multimeter to positive side of battery.
3.Connect positive battery cable to positive cable of multimeter.
4.Measure the amps being drained from battery

 

It looks like this thread is very old, but I have a 98 Maxima with the same exact problem. Has anyone figured out what causes the BCM to draw current while the car is shut off? Any solutions? Thanks.

 

The car is supposed to draw current when turned off. Things like the alarm, clock, radio and ecm use power. The only question is - how much. The car should start up after a week, but probably not after a month.

 

I know it's long but this should help answer your questions.
http://forums.maxima.org/4th-generat...rain-help.html


I checked my 98 SE which works normally and does not have this problem. I opened my hood and checked current with everything else off and closed. The draw was approximately 0.1 Amps = to 100 milliamps. If I depress the switch that senses if the hood is closed after about 30-60 seconds the current draw goes down to about 0.01 Amps or 10 milliamps. This must be the sleep mode kicking in. That is quite a difference. I can understand if another switch from the alarm system is malfunctioning or missing, the car would never go into sleep mode.

0.1 Amps is enough to drain the battery over the period of 1-2 days but you should fix it to work properly as noted above so that it does go into the sleep mode.

 

.1 Amp draw on a battery rated 750 A/H will last approx 7500 hrs.
That's about 187 days.

 

Your math is probably correct. You would need to read the thread link I provided. Apparently it was enough to drain Matt's battery because once he got it into sleep mode by replacing his trunk switch he no longer had any issues.

I've read about others that had drain issues due to a faulty hood switch that had the same problem. It appears that if the car does not go into sleep mode it drains the battery rather quickly.

 

My son's '96 fell victim to this parasite a couple of month's ago. What was previously a daily driver turned into a bi-weekly driver after he went off to college and the car sets in the parking lot between trips. I finally decided to tackle it this past weekend and thanks to all the comments on this site I was able to figure out what the BCM fuse was for (bowel control movement?) and how to stop the drain. My ammeter read the same 95-105 with the fuse in then dropped to aroun 40 with it removed. As the remote has not worked in several years (I previously spent lots of hours trying to chase that issue down and finally gave up) I decided to remove the 7.5 amp fuse. From what I can tell the only function impacted was the ability to lock the doors using the switch on the driver's side panel with the key turned off. My son chose this option over having to disconnect the negative battery cable after each use. Thanks again for all the comments and help!

 

I bought a Infiniti i30 with some front end damage. The battery worked fine until i started working from home and not using my car as much. After buying a new battery since autozone said it was bad (which it was), and pulling some fuses out I read this amazing thread. The hood is bent up a little where it should push the button down, a few strips of tape later problem solved until i can get a new hood. Thank you thread.