Dashcam USB power from auto dimming mirror

[Hobbesgsr]

After additional testing I have some bad news and some good news:

Bad news: Don't use this method as it somehow switches your backup camera on while the car is on...even while driving. Unplug the 12v to 5v USB adapter and the camera turns off and everything is back to normal.

Good news: You can use this method to switch your backup camera on while the car is on...even while driving.

So now Plan B is to tap into the overhead lighting cluster.

Bought one of these 12v to dual 5v USB adapters.

Borrowed this well documented method of tapping of power from the auto dimming mirror port.

Checked the switched power and polarity Of the 3 black wires. The left is positive and the right is negative.

Tinned, soldered and shrink wrapped the leads. Tested 5v successfully. Mounted with double sided tape and tucked and Velcroed together.

Done!

 

[jdonalds]

Awesome. Good job

 

[tim]

Bought one of these 12v to dual 5v USB adapters.View attachment 1490
Borrowed this well documented method of tapping of power from the auto dimming mirror port.

Wow, awesome! BTW, do you have any pointers to the documentation for the mirror port? Is that in the owner's manual? Thanks!

BTW, how did you physically attach the dashcam?

 

[su_A_ve]

So either it is drawing power switching the camera on, or it gave power to the reverse light detection circuitry?

 

[Odobo]

Isn't it more work and more things sticking on the windshield doing it this way than just run the wire from the fuse box?

But I would totally do this just to make a switch to turn on the backup camera...lol

 

[jorgie393]

So either it is drawing power switching the camera on, or it gave power to the reverse light detection circuitry?

There is another THEORETICAL way that the 12v-5v converter might be causing problems. These are “buck converters” which can generate noise not only on the output, but on the input voltage. Sensitive circuits might then be affected by variations in their power supply. There are various solutions (putting an inductor in line with the converter, etc—google “input and output noise in buck converters explained” but looking for an alternate power source, as OP is doing, is probably the best solution.