2019 - Waterproofing antenna installation point + routing

Does anyone know what the part number is for the grommet harness on the right side of this picture?

That's the piece I'm trying to find, but can't seem to get anywhere.

Alright, I finally finished my antenna install, at least as much as I'm going to do for now. It's far from perfect, but I learned a lot along the way.

For my grommet, I ended up modifying a Jandorf 1-1/2 in. Dia. Rubber Grommet from Ace Hardware.



I enlarged the hole so it could fit 1/2" split flexible tubing through it.



Next I used a hacksaw and made the groove deeper so it would fit the roughly 15/16" hole that I was putting it into. After that, I beveled the inner side so it would be easier to slip into the hole while still ensuring I have a fair amount of rubber sitting on the inside lip for waterproofing.




My decision to make a custom grommet was not one I made without trying quite a few alternatives first.

1. Factory power lift gate grommet
   • Subaru only sells the grommet with the power lift gate kit. I wasn't going to buy a $200+ lift gate cylinder just to use the grommet.
2. Trunk door grommet
   • I considered buying one of the grommets that connects the trunk electrical connections to the body. Subaru doesn't sell it separately.
   • Also, the hole in the body is almost 1 3/8" diameter, so the same grommet wouldn't fit in the hole I have anyway.
3. Rigid irrigation right-angle connector (would be inserted through a hole in another grommet of sorts)
   • The idea was to angle the connection exit point down to help prevent water from getting in.
   • The antenna wouldn't fit through it without me cutting the end off and re-terminating it (something I'm not versed at and didn't want to take on)
4. Tail light grommet
   • Exactly what I'm looking for, but not sold separately.

Trunk door grommet:


Tail light grommet:



The good news is that my custom grommet fits!



I tried using clear flexible tubing through the hole, but I was worried it would bend too much when the trunk closes and compromise the seal. The black flex tubing had a lot of challenges, notably, the inner diameter is exactly 3/8", the diameter of the antenna connection. Running the antenna connection through it was a pain. I had hopes of using the tubing all of the way down into the trunk area so I could then plug it in case water gets in, but I gave up on that pretty quickly.

Since it was split tubing, I needed to seal it, and sealing it was where I started running into problems. I tried heat shrink, but it made the tube a hair too small to fit the antenna. Initially I used several layers of electrical tape, but the pressure on the tube also made it slightly too small for the antenna. In the end, I did use electrical tape, but only a layer or two.

With the cable dropped through down into the trunk, I used a small piece of flex tubing to hold the cable in place while ensuring it can wiggle a little if it needs to:



Here's where it exits the rear pillar:


Routing the cable to the front, I tried to protect it as much as I could, but found one cable path (that made sense at the time) that ends up resulting in a pinch point once the foam panels are reinstalled:


My final solution was to run it above that metal brace and push it as far back under the plastic panel as I could. I didn't have a great spot to add another guide tube, so I used electrical tape in a few areas.

(hit picture limit, to be continued)

To waterproof the grommet, I initially used GE clear silicone:


But after a week or two of drying, it was coming off around the tube, so I got a different kind of sealant from Home Depot. I think it was Permatex Clear RTV Silicone (can't find my tube with the leftovers). In retrospect, I should have gotten the black sealant. The clear stuff looked great initially, but eventually turned yellow


It's holding though!


Back inside, the cable runs through a gap along the side:


Another view of it:



In the rear seat area, this is what it looks like:



I wanted to remove the rear sill plate and run the cable under the carpeting, but it didn't cooperate. I wouldn't get the sill plate to unclip. I got it undone enough to get the cable pushed up under it and then tucked it between the sill plate and the carpeting up to the front.


It isn't really noticeable I used some velcro to "clip" it onto something more stationary to help prevent it from being ripped out accidently.

I used velcro to mount the radio under the driver seat, and the mic to the carpeting right next to my right leg. I sleeved a cable extender for the antenna so I can disconnect the radio easier if needed. I also sleeved the radio power connections, which go up and into the center console. I didn't take apart the center console and re-route power like others have done.







(to be continued, picture limit)

Antenna extender connection:



Back outside, here's the antenna mount:







Since the antenna sits right next to the roof rail, I bought a cheap pack of foam crossbar protectors and used one one of them to provide some antenna bounce protection (when it's folded down).


The above picture is a bit old. Since then, I've ziptied the cross bar protector in place instead of using the cord it comes with. A small strip of velcro holds the antenna to the foam pad when I'm not using it.



Along the way, I learned a lot about some of the connections in the back seat area. Notably, the rear airbag impact sensor is mounted directly in the middle of the rear seats, on the front. For that reason, I needed to disconnect the battery while I ran the cable. Here are a few of the diagrams I was referencing (with annotations added).






When I get back into dry and warm weather, I might pull off the silicone and replace it with black silicone. For now, it's working well.