You have 4 tstats.
1. 120 side is the regular tstat at either 130 or 140. The wire connecting that tstat to the other tstat is the ECO(electronic cut out), that is usually preset at 180. This tstat is a SAFETY stat to prevent overheating if the main tstat fails.
2. LP side is the exact same as above.
YOU CANNOT SAFELY BYPASS THE ECO AND INSTALL JUST A 140 TSTAT.
As I stated, I have never seen any aftermarket tstat kit for a Suburban, What you have probably seen is the ATWOOD w/h aftermarket kit with either a higher degree tstat or the adjustable one. Doug
