Hello, Hoping someone can help, we’ve had issues with our furnace, it’s a W96T WeatherKing, the furnace is stuck on Cool Mode. When it boots up, it automatically registers a “C” and activates the fan, condenser, etc when the thermostat is set to heat. This is a condition that remains after we had to replace a faulty motherboard. So we’ve since replaced the wiring from the thermostat to the furnace to rule that out. I’ve had to disconnect the A/C wiring so the condenser isn’t running 24/7, but the fan still runs cause it thinks it’s cooling. I’ve even tried to disconnect the Y wire and the furnace won’t function cause the board is trying to activate the C code, but can’t without the Y wire connected. Are there any ideas what other wiring or devices on the furnace I should check or replace that might be causing this strange problem? Thanks so much in advance. [img]https://cimg0.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/5b18207c_7738_49c8_b469_16e5d13094bb_e713531885ebe57a4881f1a86e1418ecc2ad4cfa.jpeg[/img] [img]https://cimg1.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/2ac708e4_308e_4415_83d3_314f07e2c93b_4cbacc59746d51d8af1a14869bd997b1ebb6f01e.jpeg[/img]

We've noticed the furnace will throw a 1 blink trouble code sometimes. When it does the spark is produced, but only for a short second and then the purge cycle is interrupted. It'll try that 3 times and then go into the lockout. However we've seen this happen in the past and after the 1st attempt (out of the 3) it would work work fine without an issue. Now it's a bit more consistent and goes through all 3 attempts and fails on all and goes into the lockout. Weird because the spark is produced, but no ignition happens. This is on a Rheem 95 efficient furnace. Board replaced last year - the spark wouldn't trigger. Could it be the board is failing again? Thanks much.