Ok, so 00 Maxima 63,000 miles, intermittent electrical problem.

Seems like a high resistance problem, however I have blown several fuses

What will happen is my windows and door locks will fail to work on occassion. 9/10 times no fuse will be blown and everything will just stop working. On occassion right after it stops working if you press down on the window switch you can hear the relay click on and off like its trying to activate, but there's not enough power to keep the coil activated.....
If I didn't know better, I would say that the circuit is connected to a circuit breaker that keeps shutting power to the circuit down, however after looking at the diagrams I see only one circuit breaker in the whole car, and it's run off of a completely different circuit that would shut down power to the whole SECU, so I'm positive it's not "popping"....
Now everyonce in a while, about 1/10 times that the windows/power locks stop working it will blow the 40A fuse under the hood that is for "power door locks".
I've looked at the diagrams and I'm not even really sure where to start. I don't know weather to look for a short somewhere or a break or loose wire.
Another thing that strikes me as odd is if I have my windows down and need to roll them up, then I can pull the 40A fuse out, wait a few seconds then get in and roll my windows a few seconds before they stop rolling up further. If I do this a few times I can USUALLY get my windows up, but this doesn't always work either...
Again, I checked the diagram and there isn't a circuit breaker anywhere in this circuit.

Oh I forgot to add: When the second 40A fuse blew, I used my ampmeter across the fuse terminals. The only time I got it above 40 amps was when I attempted to roll up all 4 windows, the sunroof, and move my seat forward all at the same time. When I did this I actually got the circuit up to around 42 amps. Otherwise I couldn't get it over around 30 at any other time, no matter what I tried.

 

Dude, I am afraid it will cost you more then $5 for the answer. How about this, the dealer will charge you diagnostic fee, $95. I'll take half of that. Plus an hour of labor for them to fix it, that even if the find the cause. I'll take half of that.

But anyways, thats your choice. You posted almost an answer to your own problem.
Here is what you do. unplug the battery. Take off your driver's seat. Look at the bundle of wires going from seat controls to different motors. There will be most lilkely 18 gauge red wire either cut or stripped of insulation and touching the metal frame of the seat. When moving the seat, or having some large object under it (like fire extinguisher), it will cause harnes to rub against sharp edge of the frame. this will send a short to Body management Unit. It also will intermitently blow 40A fusible link in engine bay.
it will also cause your seat not to work when get off of it.

LEt me know if that was the cause.

 

Oh yeah, forgot. Splice in a new piece of wire in there, make sure its the same or smaller gage (smaller number, like 16 ). Leave the harness loose under the seat, because from factory it was tight against the frame.

 

He also forgot to add that he's just kidding about the fees.

 

No dude, I am not kidding about the fees. If you don't pay, i take your car.

 

Get a new car...

When do I get my $5?

 

he said diagnose the problem... not solve it.

 

You think I'm going to pay you 1/2 you got another thing coming.:-). $5 is my top offer, only reason I say $5 is because it would take time to review diagrams and give suggestions to help me pinpoint the problem, I doubt it's a wire under the seat.

If a wire is shorting under the seat then please explain why sometimes it just doesnt work. You could say maybe its a power side broken wire (high resistance) that sometimes shorts to a ground, thus blowing the fuse. However this still doesn't explain why the windows/locks intermittantly stop working and no fuse is blown.....The diagram shows the window and locks going directly to the secu. (on a seperate wire than the seat.) so in theory it would be impossible for it to be a wire under the seat unless there was a blown fuse/popped breaker everytime the windows stopped working.. Obviously they all use the same power source, and that source checks out fine with a meter.

 

I'm not trying to get $5 out of this but I wouldn't mind trying to help. I would guess it is a frayed wire making contact to ground at one point or another along the circuit. Were I to happen another guess as to where, I'd start by looking between the door and the chassis (i.e. under the hindge on either door) and then move on to the switches themselves...

Why is it sometimes blowing a fuse and other times not? First, go out and pull the positive battery cable off your car's battery post. Does it start, no. Next, put it partially on the post, just enough to make the interior lights come on. Does it start? No. What is going on? Your car is drawing current but at a lower rate than it normally would be were the battery cable to be making complete contact. This is why the gauge of the wire going to the alternator and starter is so high; to provide an adequate pathway for the current. Now, completely put the battery cable on the post... vrooom, vrooom, you're up and running.

Now imagine a wire that is frayed and partially touching the chassis and grounding itself out... sometimes. When it is not touching the chassis and the strands are together enough to provide adequate power, it works just fine. When the wire strands are barely touching, not enough power is going across the wire to make the locks work, but enough is going to make the locks "make a noise;" the same way the lights in your interior work with the battery cable barely touching the post but the car won't start, power is flowing, but not enough. And when the frayed wire is touching the chassis, zap, you blow a fuse.

Now I could be dead wrong but this has been my experience with a lot of different cars. When a fuse is blowing only sometimes and a component is working only sometimes, you have a wire that is grounded only sometimes... And given the location of the "only sometimes" working component(s), I'd start by looking at the obvious.

 

Dude, you don't have to be a smart *** about it. I don't need your money. thats probably all you got after spending on coils, rotors and MAfs. i just wanted to give you a clue about EXACTLY the same problem I had.

So get yourself a wrench and take off that seat and look under it.Don't forget about the yellow airbag wire.

 

Alright I'll check it.....Don't take it personally, just doesn't make since in theory why it would stop working and 9/10 times not blow a fuse.. LOL on the rotors, coils and maf. I've been lucky enough to just get by by turning my rotors so far and had to replace the plugs/coils once. My tranny was acting up a few weeks ago and suddenly the problem stopped, so I fear a partial rebuild in the next year

 

so whos getting the 5 bucks? if no one wants it, ill take it!!

 

It sound like you have poor contact at the fuse. I had the same problem on another car. The dash lights would go out, tail lights would go out, and sometimes the warning lights on the dash would come on even though nothing was wrong. Fuses were never blowen. but the one that controled those items just wasn't make good contact sometimes.

 

something physically stuck on the lock mechanism?

bad contact (happened to one of my power buttons)? if it's blowing a fuse on load it means it's trying to do something and failing and overloading the circuit. quite obvious i know but my first guess would be a mechanical issue.

 

Well sort of. Following your advice I waited until everything started working again and put maybe 3-5 ft pounds of force onto the seat with my hand and it stopped working, I would let my hand up and everything would work again. From this point I removed the seat and found no problems. Disconnected all harnesses and checked all the wiring and found nothing wrong. I'm thinking there are some wires between the brackets and the bottom of the seats that aren't accessible without taking all the attachments bolted to the bottom of the seat off. But it was getting ready to rain so I quickly bolted everything back up...
However since I've pinpointed my problem to something under the seat, and I am a man of my word, pm me your paypal address and I'll have the $5 to you asap.

 

circuit aint that hard is it?
my guess is that u have a bad relay. though they usually don't fail, there have been ones that do. but then it wouldn't explain the blown fuse..
well that's my suggestion. now send me my $5 =)
also, in your first post, high resistance wouldn't cause the fuse to blow. like you tested, high current causes that.
V=IR and V is pretty much constant, though it can fluctuate from a not so good battery of 11V or so to a charging state of almost 15V

whoops, too late. i guess he gets it, but hey, if he doesn't want it let me know! =)

 

money sent Thanks.


Yea, I understand basic electrical theory. I should have clarified that sometimes it acts like a high resistance fault. (components just stop working like there's no power or ground), and every once in a while it would blow a fuse. (low resistance fault)

I may have to go look at the diagram again because although the windows/locks/seats all use the same power, but once they leave the secu they are on seperate circuits, so it just didn't make sence to me that it there was a high resistance problem (possibly intermittant high resistance wire broken shorting to ground once in a while.) under the seat because that doesn't explain why the windows/locks would stop working if it was high resistance (only if it was a short and blew the fuse everytime). I'm going to have to look at the diagrams a little closer and I'm sure I'll figure out exactly what's going on.

I'm in a hurry, maybe if this sounds confusing when I read it later I'll clarify a bit better.

 

I had a similar problem when I first purchased my car. It ended up being the SECU being fried up causing the short. Thank God it was under warranty still.

 

Man I wish I knew Half of what you know about diagrams and how the electrical stuff flows on the diagram. I worked with Chinook Army helicopter diagrams and I always had to call an Avionics guy over to try to explain the stuff as you are.

Although I have no experience in this area, It was good to see you actually check what Nicks79 had to say about looking under the seat. Sometimes diagrams and wire troubleshooting isn't all in the manual, rather experience with the system helps too and is sounded like Nicks had the experience while you had the "BOOK SMART' knowledge. Just glad you looked.

Hope this thread continues so I can learn more about electrical and how to resolve your dilema.