2014 QX70, possible BCM failure

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trekl
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2014 QX70, possible BCM failure

Postby trekl » Tue Mar 29, 2022 1:19 pm

After a recent car wash, my left door would indicate open all the time. Door looks will not work with the handle button, right window no longer has auto control and of course the dome lights will not extinguish. Disconnected the battery for about half an hour, problem remained. ODB sensor detects NO CODES. Swapped the driver and passenger door switches and the problem didn't move. I'm thinking it's the BCM, any assistance would be greatly appreciated.


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VStar650CL
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Re: 2014 QX70, possible BCM failure

Postby VStar650CL » Tue Mar 29, 2022 2:28 pm

It's possible it's the BCM, but not likely. That's a simple grounding-switch circuit, and the BCM inputs are pretty robust.
It's more likely there's a water problem in your door from clogged drains, or a leaky sunroof or windshield that's flooded a connector in one of the kick panels. It's also possible it's a coincidence and there's a bad wire in your door umbilical or something like that, but I dislike believing in coincidence before checking out the obvious.

trekl
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2014 Infiniti QX70
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Re: 2014 QX70, possible BCM failure

Postby trekl » Tue Mar 29, 2022 2:39 pm

VStar650CL wrote:
Tue Mar 29, 2022 2:28 pm
It's possible it's the BCM, but not likely. That's a simple grounding-switch circuit, and the BCM inputs are pretty robust.
It's more likely there's a water problem in your door from clogged drains, or a leaky sunroof or windshield that's flooded a connector in one of the kick panels. It's also possible it's a coincidence and there's a bad wire in your door umbilical or something like that, but I dislike believing in coincidence before checking out the obvious.
I'll tear into this weekend, hopefully I can find something to avoid the costly BCM.

trekl
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Car: 2014 Nissan Altima SV
2014 Infiniti QX70
2016 Nissan 370Z Nismo

Re: 2014 QX70, possible BCM failure

Postby trekl » Thu Apr 07, 2022 9:01 am

It was indeed a BCM issue. After an expensive visit to the dealer, they found a single loose wire going into the BCM that was causing the failure.

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Re: 2014 QX70, possible BCM failure

Postby Ilya » Thu Apr 07, 2022 3:07 pm

Thanks for posting back. Moving this to the QX70 forum though!

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VStar650CL
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Re: 2014 QX70, possible BCM failure

Postby VStar650CL » Thu Apr 07, 2022 3:12 pm

trekl wrote:
Thu Apr 07, 2022 9:01 am
It was indeed a BCM issue. After an expensive visit to the dealer, they found a single loose wire going into the BCM that was causing the failure.
I'd be interested to know exactly what it was, if perhaps you spoke with the tech. I've seen BCM's die from car washes before, but it's always because of drowned relays, usually from a missing cover on a fuse or relay box. The relay drivers in the BCM are all transistors, so even a low-grade water short between a power terminal and a coil terminal will act like a shorted coil and blow the transistor. If they just replaced the BCM and didn't get to the bottom of why it blew, you could end up with the same issue all over again.

trekl
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Car: 2014 Nissan Altima SV
2014 Infiniti QX70
2016 Nissan 370Z Nismo

Re: 2014 QX70, possible BCM failure

Postby trekl » Thu Apr 07, 2022 3:17 pm

From the bill: BCM getting open signal from drivers door switch, loose pin at BCM connector M119 pin 13. Repaired pin, reset all codes and tested all systems. 3.5 hours of labor for a resounding $521.50.


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