This afternoon, our Ruud furnace suddenly stopped working. After poking around a bit, I realized that the 3A fuse on the control board had blown. I ran to the hardware store and replaced it, but no luck... still not working.
I looked around a bit online and found a lot of references to the thermostat wiring as a possible culprit, and a few minutes with the multimeter later thought I'd found a couple wires that might've been shorting together. Luckily enough, the installer has used a cable with a few extra, unused wires, so I tried connecting the thermostat with those instead. NOPE.
At this point, I've followed some other advice I found and disconnected ALL the wires from the thermostat and condenser from the furnace control board, but the 3A fuse STILL blows the moment I press the blower door switch. I'm pretty much at a loss now... Any ideas?
I'm not certain of the specific model, but it's a Ruud furnace/AC... this is the manual I have for it (ours is an upflow model).