Seat heaters - either on or off

So, I've noticed in my 2016 TP that my seat heaters only seem to have 2 settings - either on, or off. I know they are supposed to be variable but I can only seem to get it either on or off. Is this common, or maybe an issue with just my car?

 

Mine have a scroller/roller, so I can adjust if I want a little heat or a lot of heat:

 

Mine has the same, but it seems like it doesn't get warm unless it's cranked all the way up.

 

Maybe yours are faulty? I had to drive back from Austin last night, so you know how cold and rainy it was. When I left I had it on low and I could feel that the seat wasn't cold. Now, my butt/lower back weren't warm, per-se but the seat was on.

As I drove, it got colder and rained harder....so I cranked it up, and I could def feel it.

Try turning it on low, then put a thermostat on it to see what the temp reads. Turn it up a little to see if it changes?

 

So I guess that was my question, if it was just a "4runner thing", or something maybe more specific to my vehicle. Sounds like something may be up with mine. I'll dig into it more then, thanks for the input.

 

I have not seen the slider to be very effective. For me, it's either on or off. Even with full heat, it's not to hot so I am okay with the way it functions.
The control modules are a couple of hundred dollars but if it's the heating element pad in the seat that's faulty, you better off buying a new seat or just letting it be.

 

Here is a wiring diagram on an earlier 5th gen, Was looking to see if there was any type of internal thermostat.