All it does is tell the ECM to a c t i v a t e the stepper motor (on the top of the carb) to the base idle speed which is the lowest permissible speed (revolutions) that the multi pole DC generator head produces enough DC current (Amps) to excite the inverter section and make ac. If it's not a switch issue or broken wire, it's an ECM issue and no point in dealing with that as the parts are expensive with a Capital E.
I had a 10 plus year old Yamaha 2800I open cradle Inverter that the economy switch was developing a mind of it's own (ECM issues) so I sold it. Ran fine, produced flawless 60hz PSW 110 current but the econ switch would engage sometimes and sometimes not. Could have been dirty contacts, could have been a bad Molex plug but I figured why bother. Just off it and get a new (cheaper) one.
Rather than incur the expense of an ECM (300 bucks on Flea bay), I sold the unit (Honda's and Yamaha's hold their value well) and got a Champion and kept some money in my pocket.
2015 Backpack SS1500
1997 Ford 7.3 OBS 4x4 CC LB