______________________________________________________________________ I posted a similer question earlier, but wanted to ask this question. If I take the two (thermostat type) wires coming from my outside AC unit into my furnace, and touch them on the R and C terminals of the transfomer (24v output I assume), I can hear my outside unit clicking and then just humming, but that is about it. Is this a good test to bypass my thermostat, and if so, can I just assume my compressor is bad? (The fan above the compressor doesn’t turn on either, but I can spin it freely by hand, so it isn’t seized or anything like that) Replies: Service Manager “Re(1):Bypassing my thermostat to test AC” , posted Tue 30 May 14:38 ______________________________________________________________________ The click and humm you hear is most likely the contactor. If the condenser is not comming on, then start by checking fuses and/or breakers. If they are okay, then you may have burned/pitted contacts, ants or bugs in the contacts, etc. BTW, connecting the 2 wires going outside to C & R will turn the outdoor unit on only, not the air handler/furnace. If you do it that way, then turn the fan switch on the t-stat to “on” so the blower will run. It sounds like you can just wire everything back up the way it was and control it from the t-stat though. FlameOut “Re(2):Bypassing my thermostat to test AC” , posted Tue 30 May 15:26 ______________________________________________________________________ I’m 99% sure there is power going to it. I checked on the unit and I have about 240v going to it. While messing around, I noticed on that relay (I guess that is what it is) I can actually depress the contacts manually,(there is like a little button in the center of it) and I get the loud hum coming from the compressor area. Also the fan doesn’t turn. The compressor is all inclosed, so I guess there is nothing I can do with that.