Cab water leak causing possessed TPMS

The new receiver didn't fix it, so they started looking at the plugs up front. The lower connectors were wet, which is probably causing the issue. I sealed it all up with silicone when I ran the wire through.

Any idea how/where the cowling drains?

 

I tossed an edit at the end of the last post for consideration.

I am shoot blanks for real knowledge. The only cowling drain would be the a/c line that is discussed in the sticky? There was a thread a while back about a pinhole in the cowling weld that caused a similar problem as yours. Also, I recall a thread about a poorly fitting cowling that let too much water by and overwhelmed the drain, but that usually causes issues on the passenger side.

 

FYI, since you don't have yours to look at, this is the left side area of mine where I tapped an unused connection for non-key power.



I can see where moisture could whick upwards to bad locations.

 

It's the lowest connector on that stack. I'm most concerned about how the water is getting in and what it looks like under the cowling. And if the grommet is exposed inside the cowling area.

 

I just took a look. The only apparent drain holes on the left side are for welded on cab reinforcements.

Here's the thing, the Taco is soaked from todays frog choker:



But, that grommet is dry as a bone:



I got home only an hour ago.

If i were to approach it as a first step, I would request proof that there is a hole in the grommet. There's is really no more damage that could be done in the area from a test.

 

Another guess since you have a 2016, have you had any issues with your door seal? I would guess that there might be more of a problem there letting water sneak behing the seal near the kick panel?

That would be another easy test.

 

Mine was bone dry in the engine compartment also. Spider webs and dry leaves were around it. He said it comes in when water gets in the cowling. I don't get it?

 

I haven't had any issues with my door seals that I'm aware of.

 

That was the area where the pin hole leak was for the other fellow.

I would pop mine off for you, but there is not anything to really see there.



Just the metal top.

For me, going through the grommet was tough just going straight. Turning and forcing a hole in the side would have been near impossible. Maybe search for the grommet part number to get a look at it?

You might want to look for any kind of evidence around the door. It might be tough with all the poking around that was going on in that area.

 

Is the side of that grommet exposed anywhere in the cowling or where the cowling drains? I tried finding the grommet part, but didn't have any luck.

 

Not that I can see. That upper 'shelf' of the FW seems to cover it.

 

Thanks for all your help. I don't understand how it's getting in there, but I just don't see how it could possibly be my wiring.

 

Here's the other thread that I was thinking about:

https://www.tacomaworld.com/threads/new-2018-problem.548770/page-4#post-17834824

There is a very light arrow in that pic that shows the location of the pinhole. The shaft of the arrow goes through the long streak of sealant on the right side of the truck.

 

Not a problem at all!

I completely agree. Even if you poked a hole in the grommet, it would self seal and maybe weep a bit, not soak your carpet.

I was wondering if the grommet might have been misinstalled? There has to be a seat on the inner side that grabs each layer of the FW. After 3yrs there would be permanent witness marks on it.

I need to be on a big screen to search for it. I'll see what I can find in the morning.

 

I will also poke around in the service manual to see what is says about the drains, if anything.

 

I would guess that you found this, but it is the best that I can do on the phone:

https://parts.foothillstoyota.com/a..._82820_6733922/WIRING--CLAMP/674470-8202.html

Of course, I did search my truck, but if you click on more images, it brings up all the harnesses.

Checking some of those part numbers on google images might get you a good pic?

 

I can't find anything in the SM about body drains (other than the sun roof) or the wire routing through the FW.

There are a lot of harness pics on google. I just searched 'tacoma engine main harness' and had to pick through pics of the left and right harnesses.

I believe your ECU loom looks different than mine on the right side, but I think the left side (accessories) looks the same. There are some decent pics of that:

https://www.tlsautorecycling.com/search/2013/toyota/tacoma/349186.html

https://www.tlsautorecycling.com/search/2012/toyota/tacoma/266461.html

What I can't tell is what seals the grommet. It looks like there might be a plastic retainer in some pics? I really wonder if the grommet might have been misinstalled to start with?

 

I just can't figure out how water going into the cowl would supposedly come out through that grommet inside the cab. It just has to be coming in another way.

 

I'm 100% positive it isn't possible for water from the cowling to get through this grommet from looking at this image.