Water Leak Passenger Side, Blower Motor Fried, Cabin Air Filter Wet

shahrkster · Apr 20, 2021

DAY 1
Hey guys,
I have scoured many a forums and finally decided to post about this here since I couldn't get any good solutions or root causes.

I have a 2015 GMC Yukon SLT with about 199,800 miles on it. Bought it from a buddy and generally its is decent and I like it. The other day, I remote started the car, got into it and turned on the heat but the blower wouldn't come on. So after some research I decided to open up the panels under the vehicle to get to the blower motor thinking it was the common resistor issue. Anyway....when removing the floor coverings I noticed the follow:

1. The weathertech floor mats I have were not wet.
2. The factor carpet was wet close to the passenger door base.
3. When I pull this off, I noticed that the sound proofing/insulation (black) was also wet
4. When I removed the panels, it seems that water had been running down the A pillar because the wiring tape and such there were wet.
5. When I removed the cabin air filter (which was way overdue) it was damp as well. HUH!!

So I wonder if water got to the cabin air filter and leaked below to the motor (right under it and where the fan fins being cut out allow water into the motor- brilliant design GM!!!).

The question is where is this water coming from?
1. I have read about the shark fin leak issues but that seems OK. No water on the roof panel.
2. I have a sun roof that I rarely open but again roof panel is dry.
3. I dont run the AC at all (I turn it off if the climate system turns it on) since it is cold here. So I am pretty confident that it might not be the AC.
4. The vehicle was parked outside and I dont recall a lot of rain at least in the prior 7 days. I know this because I have been watching it to fix my yard (seeding, etc.)
5. The Car is parked in the driveway at about a 5-8 degree angle, front/nose down.

So what gives?
What would be the root cause?
What would you do to diagnose this leakage?

When it comes to the blower motor, its receiving the 12V but it isn't running and the fuse is fine so its fried.

DAY 2
OK. So here is some more detail. I changed the cabin air filter yesterday (day 1) evening. Brand new, dry to the bone out of the package (of course). Since I changed the filter, we had rainfall last night and this morning (morning of day 2 about 16 hours later) It wasn't hard rain but it wasn't a drizzle either. Since I changed the filter I have not driven the vehicle one inch.

After I posted the original note, I thought I would check the cabin air filter to see if it is wet. Low and behold, it was wet in a portion of it. See picture. Inserted into the filter assembly, the wet portion would be to the left side of the filter and this coincides with the air intake (I believe) for the cabin.

Any thoughts or guidance on if there are already solutions out there to fix this? Or do I need to go through the whole 9 yards of testing with water?

RayVoy · Apr 20, 2021

The problem has to be connected with the grill at the base of the windshield.
All outside air that is drawn into the cabin (through the filter) comes through this grill.

We had someone on here last fall with a leak into the cabin from this area, I believe his was a worn out seal.
However, I think I remember discussions about a drain tube from this area to the underside of the truck.
I suspect yours has a drain, could it be plugged?

I also read about the recalls for the '14 to '18 trucks, I think I remember something about a recall for a problem in this area.

shahrkster · Apr 21, 2021

Thanks for the reply Rayvoy.

So I did the following today:

1. Pulled out the air filter to check if it was still wet. It was not. It had gone dry. Of course we did not have any rain here the last day or two.
2. I checked the drain plug to see if it was choked. I removed the 90 degree angle pointing down. Then I made a wire out of 4 strands of thin gauge wire and shoved it in the drain plug. I didn't feel any resistance extent for what I think is hitting part of the assembly. It continued to go in after a little shove. I was able to pull it out just fine. No debris or anything of that sort. I don't believe that the drain plug is the issue.
3. Next, I cut out a piece of cardboard by tracing the filter to use in place of the filter while I did some drench testing.
4. I placed cardboard piece in place of the cabin air filter and poured water around the cowl and the air intake opening. I then expanded the pout to the center of the windshield and then poured it across the whole windshield. About 2 gallons of it. I did not notice any drainage from the plug (aforementioned) and neither did any water hit the cardboard piece in the air intake.

Maybe I need to keep pouring it for a while. I must have poured about 3 gallons of water.

I looked at where passenger side was wet. I noticed that the floor was more wet compared to the wall (floor has the carpet and the mat. The wall has the insulating pad). In other words, the floor seemed to have gotten wet and this tells me that there is water coming from elsewhere and that the drain plug isnt the issue.

Thoughts?

What should I test next? I am thinking about taking out the cowl.

Water Leak Passenger Side, Blower Motor Fried, Cabin Air Filter Wet

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