Noticed my battery in 2004 Nissan Titan starting to lose juice after a day of sitting. Installed new battery cleaned the leads and still draining battery. Hooked up multimeter to check amp draw. With the key off it draws 9amps every 15 seconds for about 2secs, constantly except when I unplug the 50amp BCM fuse located in box by the battery. The only mods I have done is headers, uprev tune. What could be causing this? Any ideas where to start to try and isolate this further?
Help BCM draining battery?
johannib
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Noticed my battery in 2004 Nissan Titan starting to lose juice after a day of sitting. Installed new battery cleaned the leads and still draining battery. Hooked up multimeter to check amp draw. With the key off it draws 9amps every 15 seconds for about 2secs, constantly except when I unplug the 50amp BCM fuse located in box by the battery. The only mods I have done is headers, uprev tune. What could be causing this? Any ideas where to start to try and isolate this further?
So last night I started to unhook the three connectors going to the BCM to see if I could isolate the issue further. With the BCM totally disconnected I was still drawing 8amps every 15 seconds for 2 secs, and 0amps the other time. After looking at some schemetics the BCM 50amp fuse splices after the fuse and also goes to the power windows in the rear of the truck. This makes sense because the fuse is labeled "BCM/PwrWnds"
The next thing I did was unhook the window switches in the rear doors. Still drawing 8amps. Unhooked the two front window switches, no change. So with all the window switches unhooked at once it was still drawing amps from battery.
I'm at a loss, does anyone have a clue what to look at next. Where are my Titan electronics Guru's? Does anyone have the OEM electronic diagram for this circuit that I'm talking about? My friend got the diagram from a website that he is subscribed to for auto mechanics and not sure if it is detailed enough, although I thought is was. I'm at a loss!!
The next thing I did was unhook the window switches in the rear doors. Still drawing 8amps. Unhooked the two front window switches, no change. So with all the window switches unhooked at once it was still drawing amps from battery.
I'm at a loss, does anyone have a clue what to look at next. Where are my Titan electronics Guru's? Does anyone have the OEM electronic diagram for this circuit that I'm talking about? My friend got the diagram from a website that he is subscribed to for auto mechanics and not sure if it is detailed enough, although I thought is was. I'm at a loss!!
My 'guess' based on your present troubleshooting is that you have a partially shorted wire in the wiring harness.
Removing the fuse stops the problem, therefore the problem occurs after the fuse. Unplugging the BCM and the window motors doesn't stop the problem. Therefore the problem lies between those points.
I had a 2004 when Titans first came out, I don't know if I can find the electronic version of the wiring, but I will look later today. But, if we assume only the BCM and window motors are on the circuit, the only thing left is wiring. Your friend with access to the wiring diagram may have the wiring harness layout that shows routing for the wiring harness and location of connectors. That will give you a start as to where the actual wires are. The next step in the process is to physically inspect the wiring harness after the fuse as it wanders through the chassis (pull carpet and trim to expose the route).
It sounds as if there is a resistive short (hot wire to chassis) that conducts for a short period of time then opens, shorts then opens, etc. If it were a complete short the fuse would blow - the solution becomes much easier, find the burnt wire and replace. For now you need to look for a discolored wire (or wires, as the short may be between the hot and a ground wire) somewhere in the wiring harness - not a simple or easy task.
Removing the fuse stops the problem, therefore the problem occurs after the fuse. Unplugging the BCM and the window motors doesn't stop the problem. Therefore the problem lies between those points.
I had a 2004 when Titans first came out, I don't know if I can find the electronic version of the wiring, but I will look later today. But, if we assume only the BCM and window motors are on the circuit, the only thing left is wiring. Your friend with access to the wiring diagram may have the wiring harness layout that shows routing for the wiring harness and location of connectors. That will give you a start as to where the actual wires are. The next step in the process is to physically inspect the wiring harness after the fuse as it wanders through the chassis (pull carpet and trim to expose the route).
It sounds as if there is a resistive short (hot wire to chassis) that conducts for a short period of time then opens, shorts then opens, etc. If it were a complete short the fuse would blow - the solution becomes much easier, find the burnt wire and replace. For now you need to look for a discolored wire (or wires, as the short may be between the hot and a ground wire) somewhere in the wiring harness - not a simple or easy task.
My thought is that if it's a shorted wire it will burn off (open) or stay shorted and blow the fuse. The amp draw is like clock work, literally every 15secs. This to me has to be caused by a switch/motor or CPU processor malfunction. My best guess is there is another splice that is coming off after that fuse that I'm not seeing in the wiring schematics. I also bypassed the fuse to take that out of the equation and it's still like clockwork. I've seen a wire intermittently short due to vibration or wire movement, but the truck is keyed off. To have a wire short in a harness at exact same time every 15secs steers me to something else.
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Interesting problem, I hope you solve the issue and post the solution.
No phone with a home alarm. LOL
I just realized I have an ex coworker who works at Nissan. We were both test technician's here at John Deere's engineering center. I just emailed him. He is a test technician at Nissan's engineering center in Phoenix, AZ. See if he can find me some better diagrams or give me some insight on the issue. Be interesting to see what he comes up with. Will def post any findings.
I just realized I have an ex coworker who works at Nissan. We were both test technician's here at John Deere's engineering center. I just emailed him. He is a test technician at Nissan's engineering center in Phoenix, AZ. See if he can find me some better diagrams or give me some insight on the issue. Be interesting to see what he comes up with. Will def post any findings.
I found the 04 wiring diagram. There are a number of circuits that branch off that 50A fuse. They all have there own fuse and include the emergency flashers, power seats, audio system, various illumination circuits.
You may want to start pulling fuses, one at a time, from the fuse block until the pulsating load stops.
You may want to start pulling fuses, one at a time, from the fuse block until the pulsating load stops.
I pulled all the fuses by the glove box and all the fuses in the two boxes by the battery with no change. I actually pulled all of these before pulling the BCM fuse. Is there some fuses in a different location that I need to try to pull. Anyway you could email me the 04 diagram that shows this circuit. Thanks for the input.
update....
So looking at wiring schematics the 50A fuse goes to 3 circuits. The BCM power, and then goes to a circuit breaker-2 that is located behind the stereo. From the circuit breaker it goes to the adjustable pedal motor and also the power seat motors. So what I found was that the cover for the passenger side seat adjusting switches was broken and my son had put it back on. When doing this he jammed the two switches that work together therefore creating a short in the circuit. I removed the cover and put it on correctly and FIXED the problem.
Thanks again for the wiring diagrams Eakes.
So looking at wiring schematics the 50A fuse goes to 3 circuits. The BCM power, and then goes to a circuit breaker-2 that is located behind the stereo. From the circuit breaker it goes to the adjustable pedal motor and also the power seat motors. So what I found was that the cover for the passenger side seat adjusting switches was broken and my son had put it back on. When doing this he jammed the two switches that work together therefore creating a short in the circuit. I removed the cover and put it on correctly and FIXED the problem.
Thanks again for the wiring diagrams Eakes.
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one of the most interesting for sure
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I had to log back in, just to say thank you to the OP. This has been a periodic issue that went away for a few years and just came back this week. Parked the truck and started troubleshooting, until I came across this aaaaaaaand sure enough. Thanks dudes. Even if you never see this.
I have no power to my adjustable pedals and my power seats. My passenger seat motor burnt up and I think that circuit breaker went bad. I pulled the radio and I can’t find the breaker?! What does it look like and where exactly is it behind there? My Titan is a 2005. Thanks
Saw this old post. Any possibility you still have a 2004 Titan wiring diagram. I have a draw that i think is from the BCM
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