Illuminating and aftermarket switch from dash light circuit (1 Viewer)

[kcjaz]

I've added a CH4x4 compressor switch and I want to have it illuminated with the dash lights like the other OEM switches. I know this is simple and all I have to do is connect the appropriate wire from the switch to any other wire that is coming from the dash light circuit but I'm struggling identifying an appropriate wire. Its frustrating because I know one of the wires going to all the other switches would work to tap into. I have the FSM wiring diagrams but apparently I'm not smart enough to read them and figure out wich wire under the dash to tap. Can anyone tell me how to read the wiring diagrams to figure this out?

I suppose I could disconnect an OEM switch connector and use a multimeter to see which wire had voltage with the dash lights on.

 

[kcjaz]

Is it the green wire from the rheostat?

I'm assuming "ILL+" means "illumination"

 

[grinchy]

Using the ch4x4 switch wire colors. Yellow to illumination +, black to illumination-

Post in thread 'The Guzzler - 2009 LX570'
Builds - The Guzzler - 2009 LX570 - https://forum.ih8mud.com/threads/the-guzzler-2009-lx570.1052021/post-14429542

I used a connector in my Lx that had this pin out, which included an Ill- wire.

Post in thread 'The Guzzler - 2009 LX570'
Builds - The Guzzler - 2009 LX570 - https://forum.ih8mud.com/threads/the-guzzler-2009-lx570.1052021/post-14352824

I ended up running a variable resistor in this circuit to set the correct level of illumination. I don’t really move the setting, but it was necessary to get it toned down, too bright otherwise.

 

[daneo]

On the 5th gen 4Runner, there was something tricky with the illumination circuit. I think the illumination voltage was constant, and the current-controlling resistance was applied to the negative side of the LED.

So if the dimming is working in reverse when you get things hooked up, that’s the reason.

 

[daneo]

TR would be Ill- in that case.

 

[grinchy]

Toyota wire colors could vary, but it was green + (to yellow on switch) and white - (to black on switch) on my LX.

 

[daneo]

Since you asked for help interpreting the diagram, here’s what I think is happening. 12v battery (maybe going to a Voltage Regulator to drop the voltage) to ILL+, through the backlight LED, through variable resistance from the dimmer, back to ground.

 

[kcjaz]

Toyota wire colors could vary, but it was green + (to yellow on switch) and white - (to black on switch) on my LX.

It looks lit green is the color from the "illumination" wiring diagram.

So, I should be able to tap any of the green wires going to backlit OEM switches? The thing is, several of the OEM switches, there are two green wires on the connectors. My guess is that either green wire would work to tap into because the switches with tow green wires are "daisy chained" for the illumination circuit. Total guess on my part though.

 

[kcjaz]

Since you asked for help interpreting the diagram, here’s what I think is happening. 12v battery (maybe going to a Voltage Regulator to drop the voltage) to ILL+, through the backlight LED, through variable resistance from the dimmer, back to ground.



View attachment 3239639

Thanks. My difficulty with the Toyota wiring diagrams is that they are not really at a true schematic level showing all of the physical wiring that is run connector to connector. They are more circuit based, not physical wiring based. What I want is a diagram that shows all of the wires on a connector on one diagram so its easy to understand what wire is related to each circuit. I'm sure all of the info is there in the complete wire diagram set but you have to find the switch or connector you are interested in on multiple pages to figure it out.

 

[daneo]

Got it. Yeah, that diagram leaves a lot to be desired to fill in some guesses.

 

[KLF]

Since you asked for help interpreting the diagram, here’s what I think is happening. 12v battery (maybe going to a Voltage Regulator to drop the voltage) to ILL+, through the backlight LED, through variable resistance from the dimmer, back to ground.



View attachment 3239639

This is generally correct, the oem wiring dims the -12v side of the circuit, not the + side. The + side stays constant at 12v, there is no voltage reduction.

 

[KLF]

So I have done exactly what you are doing, installed a CH4x4 switch in the dash and wanted to make the illumination work with the dash lights. It's not hard, but the only problem is you can't make the illum in the switch dim, it stays at full brightness. Mine is from 2019, maybe they are different now.

You just need to find a green wire on any existing switch, I used the one on the CDL switch. This is the constant +12v illumination circuit. Every Toyota that I have ever worked on since the 80's has been green on the illumination circuit. Just like ground is always white with a black stripe.

Found this card in my notes, maybe your switch is different:

So in my case I connected the Red2 wire on the switch to the green illumination circuit. Works fine, but like I say, it doesn't dim. Unfortunately the - side of this internal LED is not provided in the connector, unless you want to hack into the switch. Is yours like this?

 

[grinchy]

On that diagram red2 and black are for illumination, green and red in and out of switch.

 

[grinchy]

It looks lit green is the color from the "illumination" wiring diagram.
View attachment 3239642

So, I should be able to tap any of the green wires going to backlit OEM switches? The thing is, several of the OEM switches, there are two green wires on the connectors. My guess is that either green wire would work to tap into because the switches with tow green wires are "daisy chained" for the illumination circuit. Total guess on my part though.

I think you want both green and white. If you just ground the Illumination circuit it will be full on brightness. I guess this is conjecture as it isn’t how I installed mine.

 

[kcjaz]

I think you want both green and white. If you just ground the Illumination circuit it will be full on brightness. I guess this is conjecture as it isn’t how I installed mine.

Thanks. Next time I open the dash, I’ll give this a shot.

 

[KLF]

On that diagram red2 and black are for illumination, green and red in and out of switch.

That could work if you connected the dimmed -12v, but it will also dim the light that tells you the switch is on. I didn't want that, since it's for the Rigid lights in my rear bumper.

 

[grinchy]

Here are the two cards I had, for the two different types of switches. I used the 2 up latched, the 2 up momentary, and the 1 up latched.

To indicate that the switch was latched, my switches used the power from being latched; this may not be universal across all the possible switches, but it was for these. The illumination circuit has nothing to do with the state of the switch. As I was using one of them to switch a ground (no +12v, just doing continuity on the ground), I had to run +12v thru the switch latch side to light the 'switch on' light, and then use a relay downstream to connect the ground.

For Illumination, it was either yellow + black - or Red 2 + black -

All the switch ill- were fed into the variable resistor and then into the white ill- on the car.

I’ll go look up the variable resistor value, but I think anything beyond 5k ohm will work.

 

[lx200inAR]

Here are the two cards I had, for the two different types of switches. I used the 2 up latched, the 2 up momentary, and the 1 up latched.

To indicate that the switch was latched, my switches used the power from being latched; this may not be universal. The illumination has nothing to do with the state of the switch. As I was using one of them to switch a ground (no +12v, just doing continuity on the ground), I had to run +12v thru the switch to light the 'on' light, and then use a relay downstream to connect the ground.

For Illumination, it was either yellow + black - or Red 2 + black -

View attachment 3239895

View attachment 3239896

I believe @KLF is correct. This is something I mentioned back when you were first connecting these. Based on the diagrams above, the switch only has one possible path to close a circuit for an LED. Whether that is the backlight or the indicator. They have discreet supply voltage but share a ground. So if you connect black to ill(-) then the lights will dim, or if you connect black to a ground lug, you will get constant output.

 

[Tex68w]

I have the same switch and I believe I used the green wire on the headlight washer harness.

 

[grinchy]

I believe @KLF is correct. This is something I mentioned back when you were first connecting these. Based on the diagrams above, the switch only has one possible path to close a circuit for an LED. Whether that is the backlight or the indicator. They have discreet supply voltage but share a ground. So if you connect black to ill(-) then the lights will dim, or if you connect black to a ground lug, you will get constant output.

Ok, I agree with that. It gives no control over the brightness of the LED, but it will turn the illumination bulb on with the car's illumination circuit. On my switches this was a very bright illumination LED, but I guess a more complicated install can address this with a pot, or even better, a pot and using Ill- on the car side to black so that the brightness is more in range with the OEM range, and dims/brightens with the OEM dimmer.