I recently installed a dash cam in my TL which has a buffered parking mode to capture events while the car is off/parked. This feature requires the dash cam to be hardwired to constant power (rather than ignition switched power like the 12V outlets). Normally, hardwire kits are designed to be used with an "add a circuit" fuse in the interior fuse box. This requires routing a pair of wires through the dash, up the A pillar, and across the top of the windshield to the camera. I suspect there is an easier/cleaner way to hardwire a dash cam in our cars.

A majority of us TL owners are victims of the infamous HFL battery drain issue, which means the HFL harness sits disconnected in the overhead console. A quick glance at the electrical manual shows pin 11 on the HFL harness supplies constant 12V on a 7.5A fuse. In theory, it should be possible to connect the hardwire kit to the 12V/GND terminals on the HFL harness and tuck the relay (low voltage cutoff) and excess wire in the location where the HFL control unit used to be. The HFL unit is super easy to access and close to where the dash cam is mounted so I would only need to run <12in of wire through the rear view mirror cover to the camera. And no ghetto add-a-circuit mess in the fuse box.

Has anyone already tried this? Curious whether it was as easy as it sounds, or if any issues came up by wiring it this way.

 

Sounds like another battery drain. I researched the issue once - people discouraged to do this due to low quality batteries in dash cams that do not store much energy that need to be taken from car battery in the end.
I hardwired my dashcam to dash light - it needed lowering the voltage.

 

https://acurazine.com/forums/third-g...e-idea-969096/

Right now I actually wired it to the inside mirror, so dash cam and radar detector power up with key on, but remain not powered with key in acc mode.

 

I have mine run the traditional up the a pillar and across. But I also have a rear camera wired to the back under trim. Very easy and invisible route. My Viofo has a battery minder that will shut down the camera at a selected voltage.

 

Finally got around to attempting this! Really happy with the way it turned out!

My idea behind this project was to provide a clean, stealthy, and non-destructive install for my dash cam by repurposing my faulty (and unused) HFL unit. I reused a few components from the HFL unit to accomplish this. I used the BlueSkySea B4K dash cam hardwiring kit that I bought on Amazon. The B4K happens to be the dash cam I'm using, but this should work with any dash cam that is compatible with a 3-wire parking mode hardwiring kit.

Notes + Pictures:
Obligatory: This is not a step-by-step guide. My purpose is to describe my own experience with this project. If you wish to attempt this project yourself, do so at your own risk.

• I reused the HFL harness connector from the HFL unit so I could connect the dash cam directly to the HFL wiring harness in the overhead console. This required desoldering the connector from the main HFL circuit board.
  • WARNING: This is for TLs with the green 22 pin HFL harness!!! Other TLs/Acuras may use a different 28 pin harness for the HFL unit. THE PINOUT IS NOT THE SAME!!!!
  • 12V constant (red) ---> Pin 11
  • 12V ACC (yellow) ---> Pin 1
  • GND (black) ---> Pin 13
• The connector was hot glued back into the HFL unit cover (since it was no longer mounted to a PCB).
• Dash cam power supply was mounted to the inside of the HFL unit cover with 3M foam tape.
• I cut out a small slot in the HFL unit cover to route the USB cable under the rear view mirror to the dash cam.
• I added 2 small cutouts where the power supply is mounted that allow me to change the cutout voltage and enable/disable parking mode without removing it from the overhead console.

Close-up of the repurposed HFL connector, dash cam wiring, and wiring diagram from the electrical manual:



Here's the hardwiring kit wired and mounted inside HFL unit cover:


Everything mounted back in the overhead console:


Installed back in the car and plugged in:


Finished product!!! Dash cam is mounted behind the rear view mirror. Super stealthy, the USB cable from the overhead console is barely noticeable. You can't even tell there is a dash cam unless you look closely from outside!! Recording while parked now works beautifully, including the battery voltage cutoff.

 

very clever!!!

 

Thanks, I just got a camera and hardwire kit. I was hating the thought of running wires from the driver footwell fuse box to camera, then I remembered I had removed my HFL years ago. Given all the run down batteries, the HFL must have had continuous power.

Before opening my circuit diagrams and working on a plan, I googled to see if anyone else had done it. Thanks for such a nice writeup.

 

 

It might be a while, the stuff hasn't shipped yet. Might be a while for pics.

 

I think this is the first time that I'm seeing this. Very cool setup!

Playing devil's advocate, my only concern is how the green connector was re-mounted. Hot glue does not hold up well in heat, especially during the summer time. I'm from Michigan where it doesn't get exceptionally hot and even I've experienced issues with hot glue before. Given that this connector is mounted so closely to the windshield with little to no shade cover, I see a potential risk. JB weld might have been a safer choice.

Other than that, this is a great setup.

 

I take your point on the glue. Moreover, I ‘m wondering if de-soldering the L connectors, and gluing the green box is even necessary.

I’m not an electrician so I may be missing something obvious.

This question is for anyone.

Wouldn’t it be simpler to connect the 2 wires directly, without using the green box. Specifically, connect wire A marked in the first image directly to wire A in the other image. Do that for all 3 wires.

 

Guess this is a good time to provide an update. The hardwire kit is still working after 2 years. Not much more to say lol

The heat resistance of hot glue is a valid concern. However, in my case the glue does not appear to have softened/reflowed at all. Though if I lived somewhere like Arizona or Florida that might not be the case. A fast-setting epoxy like JB weld would certainly work in place of the hot glue. The main thing is the adhesive needs to be thick and fast-setting so it fills the gap between the connector and housing while it sets. Something thin and runny like super glue would not work without making little shims to fill the gaps.

Splicing the factory harness (connecting the wires directly) will work perfectly fine if you just want something quick and easy that doesn't require soldering. So it's really just personal preference. I prefer the way I did it because:

1. It keeps everything as close to factory as possible. Everything is plug and play. The final product is basically indistinguishable from the factory HFL unit.
2. It allows you to do everything outside of the car on a table.
3. I already had all the tools I needed like a soldering iron and desoldering kit.
4. Last and probably most important doing electronics projects like this is a hobby to me so I don't mind spending extra time doing it "the more fun way" (to me).

Aside from being less effort and requiring fewer tools, splicing the harness also allows you to continue using the HFL unit if yours still works. In my case the HFL unit was already dead and I have the USA spec BT module so I had no use for HFL anyways.

 

I would 100% wire it the way OP did. Retaining an OEM look and also more importantly, the function, is the best way to go about modifications like this in the event someone changes their mind or wants to revert back to stock

Typically, I try not to splice into factory wiring harnesses inside the car unless I absolutely have to.

 

Thanks for replies.

Unfortunately, I removed module years ago to do the bake fix, forgot where I put module, so I'll need to splice.

 

Hi, I'm on that summer project, just one conern, what about the abnormal battery drain? which differ Shows a dash cam vs a
malfunction HFL module?

 

well if you would remove the HFL module, it wouldnt be draining anymore

 

take the module part off and use the holder/pins only for getting power without damaging the wires.