Determining pinout of OEM switch?

[matthewkristof]

As the title suggests, how does one determine the pinout/wiring of an OEM switch when searching here or on google yields no results?

I want to install aftermarket heated seats, but would like for the switches to have some sort of backlight, preferably amber to match the rest of my gauges. I found a heated seat I want to buy here, and notice that the switch is a simple on-off-on rocker switch (hi-off-low). I've had good luck with Dorman in the past, and want to go with them.

I managed to find a backlit OEM Toyota switch that will fit the blanks in the center console (with minor adjustments) and is an off-on-off switch. Part number 84751-60100 for the left and 84751-60090 for the right. This part comes from heated seats found in Land Cruisers in the late 90s and early 00s. A google search yielded some results, and I was able to find a picture of the back pins on an ebay listing here.

I'm guessing the two middle pins are for the illumination circuit, but how do I determine where/what goes in the other ones, given that the heated seat has three poles?

I appreciate any and all assistance from an OEM guru!

 

[CookieRoe]

I can't find any pinouts online, but I do have the "service manual" of the closest 4Runner I have.

Heated Seat diagram:

next page:

A few additional questions:
1) I don't know the pin orientation of the LC switch you have (want)
2) I'm still trying to decipher our own switch pinout. LOL

At least some info on her could help.

 

[matthewkristof]

I managed to obtain a wiring diagram and a pinout from Airtex (OE distributor), but I am not sure how to read them.

In relation to the Dormon seat heaters having three poles and an hi-off-lo functionality, is it even possible to make the two work in unison?

Attached are the diagrams. [MENTION=50507]CookieRoe[/MENTION], maybe you know!

 

[fourwd1]

Those seat heaters draw 25-30 Amps, what gauge wire are you using?
Are you using relays between the switch (control circuit) and heater (load circuit)? You should be. No you have to.

 

[Toasty95]

Were you ever able to figure this out? I’d like to do the same thing you’re doing, but that Land Cruiser wiring diagram doesn’t really tell the full story.