OEM seat heater - disable only seat cushion element

Hi everyone,
I’m apparently getting older and having back issues, would like to use the OEM seat heater in my 2020 with just the back portion on high, and disable the butt portion.
From what I’ve read online, the seat cushion (butt) element has 3 wires going to it, and the back element has 2 wires. While some have theorized the controller/amp runs the elements in parallel in high mode, and series for low mode, I’m not sure I particularly agree with that assessment as the switch has 3 heat settings.

hoping to gather more info on this topic, does anyone have access to wiring diagrams for the seat heater system they can share?

I’m actually kind of surprised I wasn’t able to find others wanting to do the same. My wife likes having both elements on high all the time but I don’t enjoy my butt getting hot and sweaty!

 

Subbed. I don’t really ever want a hot grundle, but have been bearing it for heat on my back

 

Here you go on the wiring diagram. The seat and back are not broken out on the schematic.
Seat Heater.pdf

 

Hm thank you so much for taking the time to pull and post that!
Unfortunately the black boxes are not detailed so may be impossible to figure out without physical digging…

 

Physical digging is always a good thing. The Service Manual most likely has some troubleshooting info and it is available somewhere here on this forum. It is however some 10,000 pages plus long.