After a heavy rain this past weekend, I go to start my 2011 g37x sedan. Drove it about 10 miles, parked it, nothing unusual.
9 hours later I go to start it, it goes to ON, doesn’t even try starting the engine. If I push the push button again, it won’t turn off at all.
Radiator fan comes on
Headlights turn on but the headlight stalk won’t turn off the headlights, windshield wipers don’t work.
Radio works, windows roll up and down, etc.

In order to turn the car off I had to unplug the battery.

there was a bit of moisture on the passenger side floor under the floor mat. I pulled the carpet, scooped out the water, and am just letting everything air dry.

 

Either the infamous sunroof drain and/or the firewall grommet (under the battery) gremlin(s) have surfaced. Very common issue for our cars. Not the easiest to repair but doable for the home mechanic.

Check all of the wiring/connectors at the BCM (passenger side outer kick panel). Make sure everything is bone dry BEFORE reconnecting the battery.

 

Yeahhh it’s definitely the sunroof drain, the upper A-pillars are pretty damp and so is the trim piece by the kick panel.

the wiring looks as it should so I’m assuming something is just wet and being spastic. Luckily I don’t have to work until tomorrow afternoon, so I’m gonna let it air out.

 

Just wanted to follow up, I left the battery disconnected overnight and left the passenger side carpet and kick panel trims pulled so the wiring could dry. When I reconnected it this morning and tried to start it, it fired right up and everything was back to normal.

 

That is good news indeed! Now to fix that damn drain...

 

Yeah, not looking forward to tackling that. I have a feeling it disconnected at the firewall.

Problem came back today, wouldn’t start, would only go to ACC. I was able to turn it off with the push button though.

Disconnected battery for 30 mins, reconnected, started right up. But this time it wouldn’t shut off, had to pull both MAF sensors to stall out the car.

 

Grab some calcium chloride from home depot... I forget the product name, but it's flakes of white material. After soaking all the water up and out of the carpets, Leave the container in the passenger footwell with all the carpets pulled back and metal exposed to dessicate the moisture. If it sits long enough the flakes should turn to liquid, and everything dries right out. Id pop the covers off the computers for good measure.

The sunroof drain isnt hard, a set of 6in+ needle nose pliars, some aquarium tubing and silicone caulk goes a looong way.

 

Did this problem ever get resolved? I have a G35 doing the same thing. Both sunroof drains leaking. Car wouldn’t turn off. Car finally turned off when I disconnected the battery and hit the start/stop button. Now car won’t restart. Yellow key light is on. The car goes to “on” on the start/stop switch. Press it and it goes off for a few seconds and comes back on lighting up the entire dash. Everything seems to be working as it should, the car just won’t start. The radiator fan is running constantly at low levels and there’s a high pitched noise I can’t isolate. Help!!!

 

Wow, that is exactly what has been happening to me with the headlights and radio/windows.

 

Having the same issues as discussed in the thread. My difference is there hasn’t been rain for a little and no known drainage issues. Did anyone figure out what is going on? I know this is an older thread. Thanks
correction: the carpet is in fact soaked under the floor mat

 

how did u get it fixed ?? Did u ever find a solution?