[Shawk]

Very helpful discussion. I needed to tap two fuses one for a dash cam and the other for a escort radar. And everything in the interior fuse box was live all the time. My 2020 cx 30 had a battery drain problem at 3 months old and this is before a dash cam and radar. Dealer couldn’t figure it out. Had to use the radar and dash came off a cigarette lighter adapter which I had to unplug every time. Jumped it 7 times over 5 months, just from random system draw.

Couple months ago, go in for service and they have a control module update, looking into what the update was, it was to address a software glitch where the ccu and bcm are suppose to shut off after 24 minutes from lock but sometimes did not.

After the update, the interior fuses I am tapped into now do turn off after 24 mins. I verified by leaving a battery powered camera pointed at the radar and left the radar on. The radar lost power after 23 some minutes. The BlackVue battery you can connect with Bluetooth as long as it gets power, I left my keys inside my house and went to my car and tried to connect to the battery but it was also offline. Also over night it discharged itself to 47%.
Fast forward 2 months, repeated short drives (less than 3 miles) over a short time without any long drives in between do lead to a dead battery time to time. As the battery does not charge enough to start the starter motor.

*Update: Finding this community had me brainstorming.
Will report back on how the following goes in a couple weeks:
A secondary fuse box powered by a relay which inturn is powered by a interior fuse panel tap. Planning on using the acc+ wire for the wireless charger in the center console as a trigger for the relay, verified it turns off as soon as the ignition is off with my phone. I went to look for the acc wire after I saw the mazda3 install posted here before. Luckily/unprofessionally enough dealer install left it dangling. Then wire my devices into the secondary fuse box. Hopefully warranty stays intact, as it’s a fuse tap for power and a splice into a dealer installed wire for a signal source.

I would go through the firewall, but I could not see the opening on the engine side, don’t feel comfortable poking around.

Also new to the community, glad there to have found this.


Final Update: RESOLVED !!

I was successfully able to install a relay and use the wireless charger wire as a trigger. If you don’t have a wireless charger you should still be able to tap into the ignition on pin in the ecu harness, it’s shown pretty well in the mazda3 charger install. If anyone wants a picture let me know I just forgot to take one. There is a open spot under the driver side dash where you can put a bolt through and mount the relay, visible in picture. Now my radar and dash cam both turn off with the ignition off. Happy to help anyone else through the process or go into more detail.

Link for relay: Amazon.com: 1 Pack 40/30 AMP 12 V DC Waterproof Relay and Harness - Heavy Duty 12 AWG Tinned Copper Wires, 5-PIN SPDT Bosch Style Automotive Relay: Industrial & Scientific

Link for inline fuse harness: https://www.amazon.com/Bussmann-BP-HHM-RP-Black-Holder/dp/B004AH4Q22

I used ATM fuses, you can use mini or ATO/ATC. Mini will help save space, I had to abandon the fuse box idea due to space issues.

 

[Shawk]

Shawk writes "I was successfully able to install a relay and use the wireless charger wire as a trigger. If you don’t have a wireless charger you should still be able to tap into the ignition on pin in the ecu harness, it’s shown pretty well in the mazda3 charger install. If anyone wants a picture let me know I just forgot to take one. There is a open spot under the driver side dash where you can put a bolt through and mount the relay, visible in picture. Now my radar and dash cam both turn off with the ignition off. Happy to help anyone else through the process or go into more detail. "

If you are using the wireless charger wire as relay trigger then why not just take power off an always on tap [like accessory fuse] ? When you start tapping ECM wires i would get nervous,

Yes, the power to the relay is coming from the interior fuse box via a 25A ATM fuse, just the way you would normally tap power for a hardwire set up if you had switched fuses (picture of the tap I used below). Not tapped into the ecu wires.

The red wire from the relay ( turns black after the white tape part, ran out of red 12AWG) leads down and then plugs into the fuse box for always on power via the tap in the picture.
( the pink red wire that looks like it’s going into the relay is the wireless charger power wire, it’s going over the top of the relay and to the wireless charger in the center console but from the picture angle it looks like it is going into the relay)

The black wire from the relays splices into another black wire for ground, visible towards the top left corner of the picture, blue splice tap. (the wire it splices into is grounded to a bolt behind the dash, not visible, I’ll update with pictures).

The blue wire from the relays leads to my two devices via two inline fuses 5A and 20A ATM fuses, they run parallel to each other with their own fuses, not visible.

Yellow wire form the relay is dead. Tied off at the end.

The white wire from the relay splices into the pink-red wireless charger power wire for a trigger source. The pink-red wire was installed by the dealership for the wireless charger. This pink red wire is a tap itself into another white wire coming out of an electrical harness. This harness plugs into one of the ecus behind the panel. I will share pictures, have to disassemble a bit. The mazda3 install points this out and if the white wire is missing it suggests a pin tap to plug the pink red wire into that plug. If I did not have the wireless charger wire to tap, I would have to tap the white harness wire myself or pin tap the ecu plug.

I feel the same way about tapping or splicing into harness or ecu wires. Glad, I had the wireless charger to piggy pack a trigger off. But in all honestly the dealership tap for the wireless charger is much sloppier and exposed than you think for a professional, update with pictures to follow.

Picture of interior fuse tap which powers the relays, for reference only, use the correct gauge. I found 12AWG, 40A at autozone for cheaper when I did this.

 

[Shawk]

Update:
Dealership tap for the wireless charger.

According to the mazda3 wireless charger install, if you don’t have the white wire coming of the wiring harness then you can use a pin tap to tap into the plug in place of the white wire.

Below is a picture of the wireless tap being tapped by me (blue tap) for the trigger relay. I tried to get both the dealership tap (pink tap) and my tap in one picture.

Note: The blue wire (barely visible in this one) from the relay was too short and I extended it using a red wire before it splices (yellow tap, wrapped in white electrical tape) into two and goes on to power the devices.

The last picture shows the organized mess of wires that hides behind the panel. You can see the two inline fuses for the two devices. You can also see the interior fuse box tap that powers the relay. The bolt visible on the top left, that’s the 10mm bolt I used for ground.

 

[Shawk]

@Shawk, I really like your idea with the automotive relay: Use the 32-pin harness -- where the optional console wireless charger accessory would normally draw its switched power -- as the relay trigger, then use the kick panel 25A power liftgate fuse as the source of relay main power.

Similar to your setup, I will hardwire a Blackvue B-124X battery to power a blackvue camera during parking mode. Hardwiring the B-124X battery requires a switched line and a ground. For my application, using an automotive relay has several advantages:

1. Does not require running lines through the firewall. I'm also nervous about tapping the switched "Engine Control System" fuses in the engine bay.
   
   
2. Taps a validated source of switched power. The Mazda wireless charger installation also uses this switched line for power, though the line itself is coming from an ECU (reference page 5 of attachment).
   
   
3. Does not require removing the A-pillar trim to access the switched line underneath. The 24-pin harness under the trim is typically tapped for auto-dimming / homelink mirror installs. The A-pillar trim is held by two retention clips and a tether clip. The tether clip is designed to prevent the trim from flying after curtain ABS activation and is easily damaged during A-pillar trim removal.
   
   
4. Will not potentially overload a switched line. The Blackvue B-124X battery has a max input current of 13.5A per the B-124X manual. Using the switched line instead as the relay trigger will not overload the switched line because minimal amperage is required to activate the relay. As a note, the max load on these switched interior lines is still unclear from what I gather. The wireless charger installation manual has a 3A fuse protecting the accessory (reference page 5 of attachment). The auto-dimming / homelink mirror may have an inline fuse of similar amperage protection.
   
   
5. Taps an easily accessible, non-safety related, higher amperage fuse (25A) for main power. Use of the 25A power liftgate fuse at F7 of the interior kick panel fuse box will not compromise safety.

Thanks for the detailed write-ups, the great discussion, and for pioneering the way for newbies such as myself.

Thank you, glad I could help.

When you do your install take care to zip tie loose wires or wrap them in foam tape, so they don’t dont rub against any hard surfaces.

Nicely done with the advantages of the approach.

Cheers to having this community!

 

[Shawk]

What should I do to get my dash cam enter into parking mode using this method?

I use a battery powered camera, the blackvue camera system has a 12hr battery which powers it. other similar systems should be available or just power the camera through a power bank and in turn the battery is charged by the car when is running.

 

[Shawk]

I plan on going this route.
I already had routed a fuse tap and USB power supply down from the dash cam to the fuse box before realizing all the fuses are always hot (ugh!)

so logician solution is to keep the fuse tap down there but incorporate a relay.

I would like to use the white wireless charging wire for the trigger on the relay but I don’t have a wireless pad in my car. Is this wire still functional and switched?

And if so, is this in the attached photo View attachment 3463
the correct wire to tap?

thank u!

Hey maybe you solved it by now, hadn’t logged in for a while. Yes, that’s the ecu power on at switch on, I might have posted a manual on the harness a while ago. It should be functional and switched even in the absence of a wireless charger. The wireless charger just used it as a signal for itself which is what you’re aiming to do to. You should not be powering an accessory of it, but you can use it as an input signal (3v-5v) for your relay.

 

[Shawk]

Hi guys.
I've just bought a brand new CX-30 a week ago and faced the same problem. What about buying a USB connector with wire (like this) and using power as ACC? Yes, it also requires laying that cable from a central console to the fuses box, but it can be under the driver's seat. So I guess in this case parking more should work.

Not sure I fully follow. Where in the interior fuse box are you planning on drawing power from ? All the interior fuses are always live so if you draw from it directly you’ll kill your battery pretty quickly when using parking mode on the camera. You can tap into the ecu harness for 5v on acc, tapping the same cable as a wireless charger would tap (instruction in previous comments) but if you need 12v on acc, then you’ll need a relay set up. I would also use an inline fuse between the car and the usb. This would prevent any surges damaging your camera.

 

[Shawk]

I wanted to use hardware kit. We know that USB power ON when you enter the car and OFF when you leave. So I wanted to connect hardware kit to ground near fuse box (-), use any fuse for + and use USB (+) as a trigger for ACC wire. The only one question if it is enough 5V that hardware kit "understand" that ACC is on.

The minimum for a trigger signal is 3V so you should be good on that.

There is a 20 min delay. The usb ports in the car stay on for 20 mins after the car turns off, and periodically they turn on and off. This can drain the battery over time, especially if you’re only doing short drives.