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Fuse tap for any device and dash cam install

40K views 42 replies 11 participants last post by  AstroKats  
#1 ·
This is really easy and shouldn’t take more than 20 minutes. Since I’ve seen many mentions in random threads but no DIY, considering one significant safety point that I found no mention of anywhere else, here you go.

Tools needed:

Phillips driver
Trim removal tools (optional)
Pliers (optional)
Electrical tape
12 V test light
Hardwire kit (appropriate to your toy)
Zip tie (optional)
Fish tape or something you can drop vertically through the dash. (I used a ligh ball chain that I happened to have in the potato compartment.)


Step 1: Find an appropriate fuse




Depending on purpose, you may want a switched power or a constant hot.

With the car off, ground the test light on the door striker (shiny metal U shaped thing).


Touch the light tip to the exposed metal on the fuse ends or empty slot terminals until you identify what’s constant and what’s not.

Next, if you want to power your device only when the car is on, turn the car on but don’t start it.
Touch the fuse metal and terminals of those that didn’t turn on when the car was off

Pic 1: Car off, no power through 7.5



Pic 2: Car on and yup, that 7.5 is confirmed switched.




Now that you’ve found where you’re putting the tap, pull the fuse If applicable. I actually used vacant terminal 1 because it’s also switched and the Subaru fuse wouldn’t fit in the tap.

Anyway; you’ll want to use small pliers or the fuse puller located in the fuse box under the bonnet (right side just above the battery. The box opens with 2 push clips; bottom corner and top center, push them and pull it up).

Test left and right of the exposed fuse box terminal to see which side is powered because only one side receives power when there is no fuse.

Note which side of the fuse is “hot” for the install.


... Continued
 
#2 · (Edited)
Step 2: Install Tap

Careful here. Make sure the end of tap’s “tail” is on the cold tested side of the fuse slot. This will force the current through the fuse. If you install the tap backwards, depending on the tap design, the current will not go through the fuse and your device will not have protection.

If you install the tap in a currently occupied fuse slot, remember that the factory fuse goes back into the tap as the closest one to the fuse box.
View attachment 282674

You can easily confirm if it’s in properly. If you remove the fuse(s) from the tap and you know there should be power (12v constant or your car is on to enable switched power), your test light comes on when you touch it to the tail, it’s backwards.

Pic 3: Switched fuse, car on, no fuse and no power.

View attachment 282676

Pic 4: Switched fuse, car on, fused and powered.
View attachment 282678


Step 3: Hardwire kit

Pop of the “Cover-Instrument Panel, Lower DR/S Outer” with a trim removal tool (I pushed it out from inside the dash because I could). The cap that covers the dash side next tot he door, this thing:
View attachment 282680

Do not connect the fuse power to the transformer (or direct line to accessory), yet.
Ground transformer or applicable toy negative wire in appropriate location.

Pic 6: Using a fuse panel hot, I test grounded a few spots and chose a nice shiny bolt exposed when removing the “Cover-Instrument Panel, Lower DR/S Outer”.
View attachment 282682


.... Continued
 
#3 · (Edited)
Step 4: Routing - SAFETY CONCERN

Secure the hardwaire device or wiring. If using zip ties, careful to not let end ends rub against the door weatherstripping. Use the pliers to cut the tails or hide them somewhere.


Remove the A pillar trim by pulling it out and down towards the steering wheel. There’s only 1 clip holding in place, as it’s designed to fit ‘snugly’. It requires a little twist to unhook it by the speaker grill.

Now you see the safety concern that everyone who installed using the ‘tuck under the weatherstripping, pillar and roof liner’ method has done wrong. They’ve all crossed the curtain airbag.

Having routed the wire(s) safely though the underside of the dash, drop your fish tape (or ball chain) down for the top to pull up the wire(s).
That white roll on the left is the airbag.


Pull the wire over top of the airbag, there’s a nice routing channel where the pillar clip goes, and secure it to the existing wires. You can see my wire resting on the white block. I used a white twist tie to secure because I did this in my wife’s work parking lot and it’s all I had handy. The white roll is another airbag view.



Now it’s at the roof liner and not in the way of the air bag, you can tuck the wire the rest of the way.

Start at the dash camera position, to take up any slack later.

If you have a Homelink mirror, you can use the factory wire cover by sliding the thicker portion down over the thinner portion. Gently twist the cover at its base and it pops out of the mirror arm. seen below but go to step 12 here: https://www.subaru.ca/content/7907/...07/media/en-ca/accessory/installation-guide/H501SSG203_H501SSG304_18_Ascent.pdf

I used a trim tool to gently pull down the liner edge and tucked as I went.



Take up slack, secure if necessary, plug in the 12v power line to the fuse tap and test it out before reassembly and put some electrical tape over any connections for safety.

Easy peasy



....Fin
 
#4 ·
Wow, that's a really comprehensive how-to! Thanks Doca!

So, does the side curtain airbag extend from where the dash meets the windshield all the way to the rear of the door? If so, then I see what you mean about running up the weatherstripping then across the roofliner. It would go right across the airbag.
 
#5 · (Edited)
The airbag starts a few inches from the corner where the dash and windshield meet.



Because of where a weatherstrip-A pillar-liner installation crosses the bag, it will prevent it from deploying properly over the driver’s door window, the red area in the below pic. However, those things come out with so much force, it’s more likely to temporarily deform on deployment and rip the wire from the liner and stripping.

The things is, the a pillar cover comes off very easily and that’s to allow the airbag the space it needs without requiring a lot of pressure and making the trim fly off inside the cabin. I figure there’s only one outcome; the force of the airbag will yank the wire from the liner (yellow line) and either the camera connector or the camera itself will be pulled off and/or the wire will end up between the driver and the steering wheel airbag.

If for some reason the wire is well secured... outcome is debatable.



For the time it takes to run it safely.....
 
#6 ·
The airbag starts a few inches from the corner where the dash and windshield meet.
Looks like it runs from there, the full length of the car.



That's also an issue with running a cable to the rear cam (why I want to go through the floor).

Good catch, Doca! Definitely a BAD idea to go up the weather stripping then across the pillar to the roof lining as others have done (including yours truly, although it's a loose, temporary install).
 
#8 ·
Haven’t had the C pillar trim off but yeah, the bag goes all the way down. So long as you can keep the wire from crossing the bag, it should ok as the bag will nudge it aside to expand.

The floor channel is easy , it’s gets tight around the B pillar and you’ll have to pop off the lower trim but I go my sub wires safely though in it within a couple of minutes.

Thanks, Joola.
 
#10 ·
Man, you couldn't have told me this a month ago before I drove myself crazy with it all... :jackie-chan-meme-sm
 
#11 ·
Lol; I recently read on BBC that a time machine is theoretically possible.

Hopefully those who did the quick tuck and go will revisit. If anything were to happen, I’d hate to hear about insurance denying a payout over a wire.
 
#12 ·
I think I successfully got the wires behind all the airbags and stuff and it won't interfere with anything. But I had a hell of a time figuring out where to plug in the tap to get the power I need. I never was able to come up with a good fuse diagram for the car. And as I put in a front/rear cam, I needed to run that wire as well.
 
#14 ·
I think the airbag can be avoided by pushing it about an inch into the roof liner but that’ll risk a loose wire rolling around and possibly making some noise. Provided the wire doesn’t cross an airbag, it SHOULD deploy normally and just push the wire aside. I’m not about to test that out.

I think the safest way for a rear cam is through the floor cable channel, under the rear seat, up the cargo trim and into the gate via grommet/boot, provided it’ll fit. However, for those needing to run a rear camera, stand by for a DIY from crosstrekmy18.
 
#18 ·
I couldn't get the A pillar trim off mine, just loose. But that might be a difference between the 16 and the 18. It certainly would have made routing the cables easier.
 
#19 ·
Maybe it doesn't have the side curtain airbag extend all the way down there? on the '18 it's clearly designed to pop off easily during a deployment and has an elasticated tie, presumably to stop the trim piece becoming a projectile.

Hey, Doca, do you have Eyesight? If so, how did you handle routing the cable around the camera bezel?
 
#23 ·
This DIY thread is great! I was going to reply to another thread, started typing and realzied it should probably be in DIY, then with photos in this thread, I thought I'd add some ideas that may fill in some gaps for those freshly wiring their vehicle.

Looking into routing for dashcam wiring... look-see became actually running all wiring. It took longer than expected (as always!) because blindly fishing and pushing cables is never fun. Running wiring down the left floor wasn't an option as there are 5 additional sets of cables running there - no more room. Here is 1 very-clean solution (step-by-step) for a hardwired dashcam...

Before diving into this
- Disconnect your battery and/or the airbag fuse!
- You may also want to test your cables/wires to ensure they're working properly before running it all
- Make sure all cabling is clear of the airbags... it's easy to do by pushing your cabling runs another inch/two
- Some electrical tape and ties are helpful to secure wiring

Drop the wiring:
- Pop open the tweeter speaker grill with a pry tool
- Pop open the A-pillar with a pry tool
- Pop open the left kick panel to expose wiring (careful to pop it straight out because of the clip)
- Drop the wiring down the hole at the base of the A-pillar and it comes out by the left driver's foot - there's a lot of wiring here so it's easier to use a fishtool... an old wire clothes hanger unbent into a straight will work, you may have luck without one

Fusebox: It all starts here...
- Get switched power, tapping into an Accessory circuit (#31) via add-a-circuit power tap
- Optional for Parking Mode (if you have it), get unswitched power for the second power wire into the Fog circuit (#29) or Trailer circuit (#1) via add-a-circuit
- Grounding can be done via screw just to the left of the fusebox - remove the cover... left cover first by the door, 1 silver screw, then the whole front face pops off

Wiring to Center Windshield
- Remove the driver sun visors (2 screws + holding clip squeezes/pops off)
- Remove the roof console: light cover and 2 screws - it can be left dangling - you may also want to remove the 2 lamps first there because it gets annoying/blinding while working in that area
- Carefully pry the top carpeted roof headliner panel to get access
- Run the USB power cabling up the A-pillar along with the existing wiring above the airbags - if deployed, the airbag will deploy in-front/over the wiring
- Pull the sufficient length of USB cable up and around to the center of the console and push it in about 3-4" from the connector - both the end and cable will dangle
- Push the length of USB cable into the roof panel between the A-pillar and the center console so that only the connector dangles
- GPS (if you have it): let it the GPS antenna and connector dangle - the rest of the wiring can be pushed into the ceiling

Wiring to a Rear camera (2-channel)
...see thread: https://www.subaruxvforum.com/forum...m.com/forum/subaru-xv-diy-how-tos-tsb/155553-diy-rear-dashcam-installation.html
- Remove the passenger sun visor
- Remove both front+rear interior roof handles (right side) - wedge the plastic clip so it pulls down (x2) and the entire handle jiggle come out
- Remove the 3 clips securing the roof carpet by pulling down on the clip to "unlock" it, then the whole clip will come out
- Carefully pry the top carpeted roof panel to get access
- From the front passenger door, push the rear-camera USB cable towards the front... you can fish the connector in the roof from the front now and pull it to the center
- From the front passenger door, push the other-end connector of the USB cable towards the rear passenger door
- From the rear passenger door, fish the connector, and push it towards the rear of the vehicle
- From the rear hatch, find and fish the connector to the rear-right of the vehicle
...almost there...
- Carefully pull the inside plastic top hatch panel off (under the top center brake light)
- Carefully remove the rubber tubing at both ends
- Fish the connector from the roof carpet, through the rear-right hole, through the rubber tubing, and into the hatch door
- Fish the cable from the rear-corner (from the tubing area) into the center hole
- Drill/file/sand down where you want to cable to pop out (in order to make space for the plastic panel to keep flush and secured) - do this after you positiong where the cable should go... compare the connection for your rear camera

Putting it All Back Together
- Clean the windshield with Windex or something similar, since you've likely left some fingerprints/smudges now
- Use rubbing alcohol/etc to thoroughly clean your mounting areas
- Mount the camera(s)/GPS units
- Connect everything, pushing any extra cabling back into the hidden spots
- Put everything back together (in reverse order)... all clips, screws, panels, lamps, etc

Configure the dash cam and have fun! :D
...okay this post is longer than I expected...ooops...
 
#24 ·
This is really easy and shouldn’t take more than 20 minutes. Since I’ve seen many mentions in random threads but no DIY, considering one significant safety point that I found no mention of anywhere else, here you go.

Tools needed:

Phillips driver
Trim removal tools (optional)
Pliers (optional)
Electrical tape
12 V test light
Hardwire kit (appropriate to your toy)
Zip tie (optional)
Fish tape or something you can drop vertically through the dash. (I used a ligh ball chain that I happened to have in the potato compartment.)


Step 1: Find an appropriate fuse

View attachment 282670
View attachment 282672

Depending on purpose, you may want a switched power or a constant hot.

With the car off, ground the test light on the door striker (shiny metal U shaped thing).
View attachment 282664

Touch the light tip to the exposed metal on the fuse ends or empty slot terminals until you identify what’s constant and what’s not.

Next, if you want to power your device only when the car is on, turn the car on but don’t start it.
Touch the fuse metal and terminals of those that didn’t turn on when the car was off

Pic 1: Car off, no power through 7.5

View attachment 282666

Pic 2: Car on and yup, that 7.5 is confirmed switched.

View attachment 282668


Now that you’ve found where you’re putting the tap, pull the fuse If applicable. I actually used vacant terminal 1 because it’s also switched and the Subaru fuse wouldn’t fit in the tap.

Anyway; you’ll want to use small pliers or the fuse puller located in the fuse box under the bonnet (right side just above the battery. The box opens with 2 push clips; bottom corner and top center, push them and pull it up).

Test left and right of the exposed fuse box terminal to see which side is powered because only one side receives power when there is no fuse.

Note which side of the fuse is “hot” for the install.


... Continued

you used an EMPTY fuse slot, number 1? i know how to tell if the socket is powered, but how do you know what the rating is? I need a slot that has 15A and hope one of the empty slots in my 2018 crosstrek limited has that rating or higher.
 
#25 · (Edited)
Any slot can handle that as current is dictated by device draw, not by available power, and the fuse is there to ensure that nothing electronic is damaged if there’s a power surge.

Unless your piggy backing off another wire harness or have a lot of custom additions, which means you will have some calculations to do, just drop a 15 amp fuse to the tap and you’re good to go.

I’d be very surprised if your device actually draws 15 amps. I had a Curt trailer harness that said a 20 amp fuse was needed but I ran it on a 10 amp fuse.

Really want to confirm it? https://m.wikihow.com/Measure-Amperage

To know how many amp hours your battery has, you need to consult the manufacturer; assuming you intend to run your device with the car off.
 
#30 ·
Thanks but I’ve had my share of stinkers as well.

Are you sure you don’t have that backwards? Using an empty fuse socket makes it super easy to diagnose. That’s why I used 1 instead of 18.
 
#34 ·
As a replacement for an old DOD Tech 300LS I installed a thinkware X700 today ...front and rear but did not remove the rear grommet to run the wire To the rear camera. I just tucked it under the head liner as I did not want to have to frig around trying to get that grommet back in to place. I was going to stick it to the plastic trim at the top of the hatch to minimize the cable length coming from the headliner but the included 3M adhesive for the rear camera would not stick to it...😯. 3M adhesive products are usually so sticky that you can stick sh1t to ice cubes with it but this stuff would not so I stuck it to the top of the hatch window. Everything is working great so unless that wire at the back bugs me...it’ll stay that way.