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.
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