Routing power cable through firewall Subaru Crosstrek Install

[kb9bny]

I would like to install a dual band radio in my Subaru Crosstrek. Usually I would come in where the wiring harness comes into the cabin. But, the space is cramped and I don’t think it would work. It seems like my only option would be to drill a hole in the firewall. I am attempting to run a power cable from the battery to radio inside the car.

 

[slowmover]

Subies appear popular. I’d search on this site, QRZ, and a broader search so as not to have to reinvent the wheel.

 

[ka3aaa]

i always used the grommet where the odometer cable is, cut a small slit in grommet with exacto knife.

 

[BC_Scan]

It seems like my only option would be to drill a hole in the firewall.

I would attempt to avoid that at all costs , its easier to find the grommet space where the factory wiring goes thru and exploit that with a sharp end of a coat hangar for example, so assuming there is space in that cavity you can push it thru the rubber material softly and use it as a fish tape to pull a string thru etc then the cable you need , much better option

 

[ak7an]

Not many vehicles today have a speedometer cable

 

[mrweather]

You could try running the wire through the hood release cable opening.

 

[VK6NCB]

I dont have a Crosstrek (XV here in Australia) to look at, but I do a lot of installs into vehicles (mainly toyotas)

the hood release cable grommet is a good option, as is the large grommet for the main wiring loom.
on my Subaru Forester, I have used the main wiring loom, put a little cut in it with a sharp knife, and used a long cable tie with the head cut off as a snake to pull 3x coax and 2x power cables through (UHF CB power and Coax, HF, V/U coaxes and power)

I would avoid using a coat hanger or similar as a snake unless you know for certain what is behind the panel you are pushing through. I will never forget the sight of smoke rising from the dash of a vehicle I was working in the back of. another staff member pushed a wire through a firewall grommet, and managed to hit the back of a fusebox causing a short.

 

[BackToEden]

Wherever you run it, be sure to fuse both the + and - connections at the battery.

 

[mmckenna]

Wherever you run it, be sure to fuse both the + and - connections at the battery.

Don't run the negative directly to the battery on modern cars. Many have a hall effect sensor on the negative strap on the battery that senses current draw and helps manage the electrical system. Bypassing that sensor and giving energy a path around it can cause issues. Most modern vehicles that use these sensors have a section of the owners manual that advise against doing that.

Run the negative to the vehicle body and let the system do it's job. It can also help with RFI. Good short ground leads for the radio are your friend.

 

[K6GBW]

I have a 2021 Crosstrek with a Motorola XTL5000 mounted under the seat. I ran a 10awg wire from the battery up under the driver's side fender in a wire loom. I routed it behind the power brake booster and then made a new hole between the booster and the main wire loom. I used a cable gland to secure the wire and routed it under the dash, again in a wire loom and under the step panel to the B pillar. This is where it is routed to the radio. The radio is grounded to the rear seat bolt. I can send pictures of the firewall install if you'd like.

 

[exkalibur]

There's a grommet in the passenger footwell that has plenty of real-estate for power cables or whatever you need to run. You need to peel back the carpet a few inches to see it, but there's a factory harness that goes into the channel along the passenger side of the car to the rear of the car. There's also one on the driver side, but doesn't have as much room as there's more stuff going through it.