I have a 2007 suburban 1500 that I added OEM heated seats to in 2016. Driver side comes on ( seat back and bottom) but shuts off after about 2 minutes. Passenger side works fine. both sides have 7.0ohms and 4.9 ohms for seat back and bottom. gm p/n 25862293 on the controller. Any trouble shooting tips before I have to throw $$$ at it. $400 for the kit and $100 at the dealer to flash the computer. I hate to just leave it, was the wife's Christmas gift.

 

It shuts off because either the controller has a weak circuit or you likely have a switch failing after heated up. Have you monitored the ohms readings throughout the entire process? What I mean is, are you reading ohms and when the problem occurs does it happen like a light switch shuts off and one minute you see an ohms reading and the next you don't or is is a gradual fall off of the ohms reading?

 

reading while heating mats were disconected.
after 2 minutes controler relay clicks and the a secon later leds on the switch shut off.

 

Relay could be dropping out then controller senses that and shuts off. I'd try changing the relays first, they are cheap enough.
Relays today are right in line along with fuse issues in the old days.