2017 QX70 Water under Driver side floor

[Patriots121988]

Jumped in my car to go out the other day and it wouldnt start. Waited a second, tried it again, cranked and wouldnt turn over. Tried a third time, car started but dashboard lights were all illuminated and reverse camera was not working, car was shifting hard and wouldnt get out of third gear. Scanned it and got a U1011 BCM Communication Lost code. I noticed the carpet was soaked under the driver floor mat so I pushed down on it and I could hear sloshing around. Removed the Driver seat, pulled up the carpeting and found water in the wells of the floor boards up high enough that it was starting to get into the module that sits under the driver seat. I shop vacced the water out, removed the module and let it dry out over night, reinstalled the next day and everything seems fine there but I cant figure out where the water came in. The sunroof drains seem to be clear and drain as they should when I put water down them. I cannot replicate the leak running a hose over the car, it seems to happen intermittently for whatever reason. The door weatherstrips seem to be in tact. I've gotten to the point where I've set up a camera in the car to check when it rains and see if I can spot where the water is entering and I was able to spot one time, water entering on the left hand side of the footwell in the front area of the driver door. You can see in the photo the ground wires attached to the frame, that is the area where I was able to see the water actually coming in. However, The jute under the carpeting would always get wet closer to the center of the foot well so Im not sure if there is a second leak or what else to check here. Finally, this car had lojack installed in it when I bought it and they installed the module under the driver carpeting which got soaked and no longer works. The red/green/white wiring you see in the photos is the wiring for the lojack module. Additionally, there is a black wires taped to the jute that im not sure what purpose it serves or if it is aftermarket or an oem wire. If anyone can shed some light on this black taped wire, I would appreciate that also. Thank you everyone in advance.

[VStar650CL]

The most frequent cause of "open" sunroof drains which still leak is a hose that has shrunk and pulled partially off the nipple at the roof end. You can eliminate that possibility by loosening the A-pillar trim and dumping water down the sunroof gutters. If water drips off the headliner in addition to coming out under the car, you probably have a detached hose. Don't forget that you also have rear drains which can only be checked by parking on an uphill. Because of the tilt of the floor, on most cars water will accumulate in front even if the overflow is at the rear.

In general, using a hose to check drains is ineffective. The best method is to open the roof and pour about a half pint of water directly into the gutter channel. You should see most of that water on the floor behind the wheel within about 5 seconds of pouring it. If you only get drips and drabs then the drain is clogged enough to matter. All late model Nissan products use the same drain fittings and have the same problem, diffuser nubs molded into the fittings which encourage clogs at the base of the hose. Those not only make snaking or blowing the drains difficult, they really need to be removed or at least broken loose to prevent having to do the job over and over again. See the pics in this post:
post6844183.html?hilit=nubs%20murano#p6844183

Here are some other common causes of hard-to-find leaks:

Clogged cowl drains - Some vehicles like gen2 Versas and Titan trucks have very small cowl drains and not a large opening into the fender like most vehicles. On those, mud and leaf debris can cause the cowl to fill with water until it overflows into the HVAC intake. Depending on the construction of the HVAC, water can wind up in either floorboard. The clue to a full cowl will be a visible waterline right at the bottom of the HVAC intake.

Floorboard seams and grommets - These can be insidious because they generally leak only when the vehicle is moving and the tires are kicking water onto the bottom of the car. Steering shaft grommets are a common culprit, as are broken seams where the floorpan and firewall panels are spackled together. To find this type of leak, jack the front end and spray the base of the firewall and backs of the fender cavities with a garden hose.

Fender seams - Like floorboard leaks, leaks where the fender joins the cowl will often only take water when the vehicle is moving. Generally the water will be ingressing at a corner of the cowl, so the best way to find it is to remove the cowl cover and spray directly into the area under pressure.

Windshield A-pillar seals - This is another leak which often shows up only when moving, because wind is forcing its way up the A-pillar and pressurizing the leak in the windshield gasket. To find these, remove the cowl cover to access the bottom corner of the shield, then spray under pressure directly up the A-pillar seam.

[Patriots121988]

Appreciate the thorough response. We actually got a good bit of rain this morning. Checked the car when the rain stopped and there is a small fuse block under the driver foot well on the left front corner of the car, the jute immediately behind it was soaked. Nothing above or to the left of it appears to be wet but you can see in the photo where im holding the just that applying a little pressure to it drips water. Also immediately under the steering column boot was wet. Im not sure how these to areas could possibly be related or if I have multiple things going on but at this point im compelled to just drill a small hole in the floor where the water pools so that it doesnt end up collecting and just drains out. How terrible an idea would that be ? I attached more pics. Please let me know if this information leads you in any certain direction that might help isolate this issue. Thank you agina.

[Patriots121988]

This is the fuse block where the jute was soaked behind it.....

[VStar650CL]

That sounds like water coming down the A-pillar. Water flowing down the pillar tracks along the harnesses and the curtain airbag, so it will usually drip off in several places at once. The trim should just pull loose after partially pulling off the doorframe welt, so I'd have a look at the back of the trim and see if it's wet back there. If there's water under the top of the trim, then you can be sure it's coming down from the roof area and probably isn't from a windshield leak. If you find it wet partway down but not at the top, then it probably is a windshield leak partway up the pillar.

[Patriots121988]

Pulled the A pillar trim off, every thing is dry, no apparent clogs in the sunroof drain tube and water runs through without issue when i pour it straight to the drain. I came across a youtube video that explains a similar issue but with a g37 and found a grommet in the firewall in the same area where things seem to mostly be getting wet in my car. Would this possibility make any sense to you? It looks like I have to remove the e brake assembly to access it but im fine with doing that if it seems like a possibility. Thoughts?? As always, thank you for your assistance.

- Anthony

[VStar650CL]

It's possible, but leaks underneath usually only leak when the car is moving. The fact that yours got wet from sitting in the rain makes me think a cowl problem or windshield seal leak is more likely.