Wiring question - defroster switch

[nakman]

I have an old defroster switch that I want to repurpose to toggle on/off a dual battery monitor. I put a "volt" sticker on it from my Aux Beam stuff to make it look fancy... going for a setup that looks like this:



So I'll run + wires from each battery into the back of the voltage display, then run the shared negative through the switch. Simple enough right? I've done this before, but not with a Toyota switch... here's what the back of the switch looks like:


Zoomed out... do I have this set up right?



My next step is just hook it up to a battery and try it... but thinking someone here has already done this. I don't really care if the light in the switch lights up, and only running negative through it I kinda think that's not an option anyway. I'll know it's on by the volt meter 4" to the right being lit up, right?

 

[nakman]

Ok so according to my multi meter, this is the configuration that makes the switch work...



which means that other terminal must be for the light. So if I jumper one of the + wires over there, think that'll make the light on the switch turn on?

 

[nakman]

never did get the switch light to come on... but don't care, the blue lights from the monitor are way bright already.



View: https://youtu.be/eOFD_jtJrzs

 

[Corbet]

Option for red monitor to reduce the brightness?

 

[nakman]

Option for red monitor to reduce the brightness?

Yeah that’s not a bad idea. I could go green also, which better matches the dash. It’s just one of these things..

https://www.amazon.com/Digital-Voltmeter-Voltage-Monitor-Battery/dp/B091YX1H15/ref=mp_s_a_1_5?crid=3DB9OSEH5DJOB&dib=eyJ2IjoiMSJ9.sdKm23Is6V_09xqaqSq9uc3lbH1l11uW2jg2Ztqax0y7hJJGzqbmxc1yPDPN7-LwJE1bELI3ZkCvFbr21k2pO3Wp31Cu5FCb86mq-8q3xRYFOqnGFQy2HlMjpWcU2GE8OLUp2MP2uYUqKioQN00DqBjRjxREjgOJJ9XZTVbOvoLlKCfRlbpRf1MIbEp1YhueVmMzU1fDlexf031oxGqG2A.9HuPPO4r6ncMl9psNz83vPi41OJhw4zh_5SkidkryvI&dib_tag=se&keywords=12v+battery+monitor+dual&qid=1766459294&s=industrial&sprefix=12v+battery+monitor+dual%2Cindustrial%2C184&sr=1-5

 

[Corbet]

Yeah that’s not a bad idea. I could go green also, which better matches the dash. It’s just one of these things..

https://www.amazon.com/Digital-Voltmeter-Voltage-Monitor-Battery/dp/B091YX1H15/ref=mp_s_a_1_5?crid=3DB9OSEH5DJOB&dib=eyJ2IjoiMSJ9.sdKm23Is6V_09xqaqSq9uc3lbH1l11uW2jg2Ztqax0y7hJJGzqbmxc1yPDPN7-LwJE1bELI3ZkCvFbr21k2pO3Wp31Cu5FCb86mq-8q3xRYFOqnGFQy2HlMjpWcU2GE8OLUp2MP2uYUqKioQN00DqBjRjxREjgOJJ9XZTVbOvoLlKCfRlbpRf1MIbEp1YhueVmMzU1fDlexf031oxGqG2A.9HuPPO4r6ncMl9psNz83vPi41OJhw4zh_5SkidkryvI&dib_tag=se&keywords=12v+battery+monitor+dual&qid=1766459294&s=industrial&sprefix=12v+battery+monitor+dual%2Cindustrial%2C184&sr=1-5

Red should be the best to maintain your night vision.

Powerwerx Panel Mount Dual Digital Red Volt Meter for 12/24V Systems

Displays 2 battery bank voltages simultaneously. Features a bright easy to read red LED display. Monitor DC voltages from 6-30 VDC. Fits standard 1-1/8" diameter hole. Rear mounted F2 faston tab connections.

powerwerx.com

 

[Inukshuk]

Red should be the best to maintain your night vision.

Glad you said that. I am always amazed at how bright other people keep screens and things. Seems it should be intuitive to have as dim an interior as possible to be able to see outside. But I suppose most people (unlike us here) drive in bright cities. My first car was a 1977 Granada and the dash lights stopped working after I installed a stereo. I had to guess speed but exterior visibility was enhanced.

 

[Inukshuk]

Forgot to mention - I use the same old switch from my FJ60 as part of my driving light circuit. My driving lights are set to come on with the highbeams using the Slee aux harness. If I want just stock highbeams I can interrupt the circuit with this same switch. And it reminds me of my 60.