Hello. I have an 07 Maxima with 45k miles. Bought it new and its never been wrecked or in a flood. Back in December I started having an intermittent issue with the power locks, windows and seats not working. This failure occured both when using the fob (locks) or the door/seat switches. The Nissan dealer replaced the BCM and thought it was working. But it only worked when I first picked it up - but after I started it and drove off, the seats, locks and windows were broken again. By broken I mean - nothing happens when you push them.

So I brought it back again to the dealer - this time they said the BCM connector wasn't pushed in tightly. So they "fixed it" and I got it back. Same thing - worked only temporarily. Brought it back again to the dealer. This time they had it two days - and now they are saying it needs a new main wiring harness - about $2700 for parts/labor! To be honest - I am having a hard time accepting this on such a new car (well maintained - garage kept - no rats!). What I notice is when I disconnect the battery momentarily and then reconnect - everything works again. Until the car is started! Then I have lock/window/seat failure again. So its like something is confusing the BCM once power is applied. Does this sound like a wiring harness issue - or is it more likely a relay or other control that is failing under load (could this be the ECM shorting)? And if it's the harness - I was thinking it could be repaired versus replaced since it's so expensive to replace. Any thoughts on any or all of this - please let me know? I am anxious to get this resolved but feel like I am between a rock and hard place. I love the car but almost 3 grand is a lot of money! Thanks.

This afternoon I disconnected and reconnected the battery and adjusted the power seat up and forward because my wife wanted to use the car. She is several inches shorter and much lighter than me. Interestingly - the locks and windows and seat continued to work for her after she drove the car to the store and back. In fact I went out there tonight and the locks were still working (I didn't adjust the seat or sit in the car)!

Perhaps this is just a fluke - but it got me thinking that maybe there's a short in the seat harness - and since she has the seat raised and she is also weighs much less than me - perhaps the short isn't occuring with her in the seat because the wires aren't being pulled/stretched. I have no idea if this makes any sense - and she plans to drive the car this week (I'll be using hers). I guess we'll know if it stays working. But - does this theory make any sense or is it probably just a fluke that it started working again?

Ok - everything is still working. It's now been 4 days. My wife is still driving the car - I haven't even touched it.

Guess I thought by posting here someone would chime in that had a similar experience. That hasn't happened so I assume this is a pretty obscure issue ... my luck! Still - I would welcome any thoughts on this - even if just opinions - especially regarding the wiring harness recommendation and in light of the fact that it seems to have resolved itself. And to be honest - I don't really think it's really fixed - not in a permanent sense. So I really don't know what the next step should be. I hate to mess with this - it may break again. But I worry that it may go out at the most inopportune time (especially regarding the windows which can't be manually put up if stuck in a down position). Thanks.

Electrical stuff is tricky. I would first buy some kind of electrical wire or connection cleaner
(I use some from Radio Shack) and make sure no dirt is in the connections. Disconnect
and spray each connection. I would use a light smear of silicone dielectric grease around the
connections and a light amount on the pin connections for water resistance after cleaning. Try to clean the wires the best you can and look for frayed insulation. If you have a multimeter you can try to see if you get 12v from the harness to the seats. The floor shop manual can tell you where these
harnesses are and if you can also check the resistance of any items too.

I would check my alternator and make sure its putting out correctly. Try charging the battery up
with a battery charger overnight as well.

It is interesting when you disconnect the battery the items seem to work again. Hopefully you just have some static electricity in the system which needed to be relieved.

Thanks for the suggestions. This is some good stuff! All of it quite do-able for relatively little effort/money. I have a feeling it's something simple yet obscure - as you say electrical is quite tricky. Even though I have been driving for over 35 years and have had over 10 cars in that period - I don't recall having many electrical issues (other than the occasional battery dying) in a couple of decades. I guess I've been lucky but I know cars have also improved in this area immensely. My worst memories with electrical were an MG back in the 70s (Lucas parts) and a Fiat in the 80s (Magneti Marelli parts). What a nightmare. Thanks again.

Well - the seat/locks/windows worked fine for 4 months while my wife drove the car. So I had to drive it the last couple of days - and the darn locks, power locks and windows stopped working again. Yes - I had to adjust the seat back to drive the car and this may be more evidence of my theory that there is some sort of short under the seat. But it's so cramped under there - I can't really see anything. Is there a relay under the seat? Does the seat need to be removed to get to it? Or is it under the hood somewhere?Thanks.

No relays under the seat to my knowledge.

Let's get you some help -
Page 46: http://www.nicoclub.com/FSM/maxima/2007_Maxima/gw.pdf
http://www.nicoclub.com/FSM/maxima/2007_Maxima/bcs.pdf

Thanks. I read the material you linked to. Not sure how to run these tests though. And its a bit cryptic when it states no ground - replace harness. Which harness? I need Nissan repair for dummys!

I re-read the symptoms. I'm leaning towards a failing BCM, which typically dies intermittently before finally croaking. Went through that on my Q45.

Should be able to find one on www.car-part.com fairly cheaply.

Thanks - but the dealer already changed out the BCM. Cost me $600.00! That was one of the first things they did. They replace it - and gave it back to me and said it was fixed. I hadn't even left the dealer lot and I tried the windows and nothing! Took it back - they checked it and said they hadn't plugged in the BCM correctly (wasn't snapped in tight at the connector) - gave it back to me. Again, I am on the road trying the windows a few minutes later and it's not working again. I know this sounds crazy - but after you disconnect the battery to work on it - and then reconnect - it resets itself and everything works. But the minute you turn on the ignition and everything gets juice - whatever is failing seems to fail at that moment. Then the seat, windows and locks all don't work. If you disconnect the battery again - then it works. But the moment you start it up - bang - not working. Unless the driver seat is in a certain position (as indicated below) - then it works fine even when you reconnect and start it.
The reason I say it's related to short in the power seat harness or some relay related to the seat is that when the seat is adjusted a certain way (all the way up and close to the steeing wheel which is how my wife needs it) - it all works fine. When I drive the car - I adjust the seat amost all the way down and all the way back (and I weigh 250) - then we see this pattern of failure. That's why I think it's related to the seat somehow - despite all the theories that it's the main wiring harness, BCM, etc. I guess I was hoping this is something common and others would say - yeah - here's the solution, it happens all the time. But apparently it's not that simple - because most people point me to some diagnostics checklist (which I a appreciate but am not able to do on my own). The dealer has all the equipments, master techs, etc - but I am not impressed in their ability at all after 4-5 visits and now their diagnosis that I need a main engine wiring harness that will run almost 3 grand parts/labor. I am not convinced that this is the issue. Why they will not listen to me regarding the seat as being a hint of what could be wrong - I don't know ... probably time to bring it somewhere else. Does anyone know a good tech/shop for Nissans in Jacksonville FL?

I'll see if I can round up some more opinions on this one. Bear with us, we'll keep plugging away... Thanks J!

FYI - A good friend (Infiniti Master Tech for years) sent me this response:

"If this car was in my shop I would remove the driver seat and inspect all the wiring through out the seat as well as the wiring under the carpet that goes to the seat. I have seen this type of thing happen several times in drivers seats where usually the heavier person will move the seat and it will either short or open a wire in the seat harness. I see the windows and the seats get power off the same bcm terminal. I have not seen where the door locks come into play. If the wire that is shorting is the can bus to the bcm maybe that would cause all of the issues."

Check the battery and Alternator. THere are numerous posts detailing wierd electrical
events when the alternator is going out

Thanks AZHitman and NutriaforBreakfast. I am going to have the battery/alternator checked as well as get the seat pulled. I believe I have one of the Duralast batteries from Autozone. I'd do a quick stop there first to check out the battery/alternator - then proceed to the seat.

Well - it's finally resolved. It was a frayed wired in the power seat switch. Dealer finally found it after I was able to convince them of the connection to the seat movement It was definitely shorting out - the insulation on the wires was stripped away due to rubbing. It appeared that perhaps the wires weren't placed correctly when the car was built - causing the insulation to be scraped whenever the seat was moved front to back and vice-versa. This led to the short and the rest of the story ... unfortunately, it was a very expensive part. Fortunately, the car didn't catch fire on me!

I had same issue with my 07 , I used your info and I unplugged seat though . Reset by taking battery cable off for 15 min . Locks and windows work now . I smelled something from seat when adjusting , was at car wash when the fail happened though vacuuming car out guess I hit switches . Gonna take seat out and check further let you know more . Thanks for info !

jdgeorgio, I'm having the same problem with my 2005 Altima. Can you tell me what the expensive part was?