[coneZONE]

For the past ~ decade or so, we thought our furnace was 2-wire control. We knew it had been replaced with a modern unit before we moved in, but the “Fan” switch on the thermostat never worked. NBD. Never really thought much.
Just being so hot these couple days, i thought i would run down and flip on the manual fan switch (like an old school furnace). Welp, it’s a modern one right? So all electronic controls, and turned out it was 3-wire control. Thank goodness for google and model numbers, i found the wiring diagrams for both the furnace and t-stat. Red 24VAC, White HEAT, and Green FAN. After some voltage testing and continuity tests, i found out the “FAN” relay inside the t-stat had been blown this whole time. I heard it click all these years lol. Bypassed the t-stat and jumped red to green. Although not A/C, at least we have some airflow through the house now