Just purchased 21 Lexus ES350 and loving it but I can't seem to figure out the mirror tap. I was able to tap into my other Lexus cars: RX350 (13 + 16), NX300H (2016), GS (16), and GX (16) without any issues. I attached a picture to assist. Can anyone help. Thanks in advance.

 

Test light will reveal where power is. White/black is most certainly ground.

 

I tried everything. I tapped the black wire to white/black and tried to everything else and nothing works. I tested the mirror tap wires on my other Lexus and it works. I can't seem to figure this out.

 

Did you have the engine running? The mirror power is off when the engine is off.

Here is a picture of the wiring harness for a FitcamX dashcam. The male and female white connectors have five wires and are connected to the factory wiring connectors. The round black connector goes to the camera. It is really easy to install. The camera only works when the engine is running. It might work on the accessory setting, but I have not tried it. You have to run a separate wire if you want the dashcam to record while the engine is off. I did not want to tear into the car to run an extra wire to the mirror.

If I had to guess, I would say the black wire is ground and the wire next to it is 12V.

 

I am trying to hook up my escort 360 redline w/ M2 dash cam

 

Regardless of tips and instructions about the color codes on wires for tapping, I always use my meter to check the voltage (to be sure I have a switched power source), and for continuity (to verify a good ground). I have found that many printed and on-line instructions designate incorrect colors; it seems that these wiring harness colors are subject to change without notice.
It can be tedious, and I sometimes have to tape a needle to the probe to get into the connector, but once I have ID'd the correct wires, the rest is usually easy.

 

Always verify no matter the source

 

$5 test light

 

Always have to verify a good ground also which a test light will not do.

 

Only way to verify ground is load the circuit, a test meter can fool you since it has very low current by design. Test light on battery positive and the ground you are trying to verify. Simple.

 

If you don't have a meter how would you even know a starting place which wire was ground and never assume a particular color is ground. You are correct in saying load test is ultimate test but sure don't want to hook up ground to wrong wire. In electronic repair I have never had an instance where I could not identify a good ground by meter as I could always tell a slight variance by even .1 ohm. In a lot of electronics even though the ground tests good parts of the circuit use the metal frame to solder and join to other grounds which caused a lot of problems for cold solder joints. In the old days for wired units black was always the color for ground. I haven't used a test light in over 60 years but I can see for automotive work a quick check of voltage would be helpful just make sure the brightness is consistent as some points might be less than 12 volts.