My Central A/C quit working last week and my brother-in-law tested the transform at the furnace and said it was bad (not putting out 24 volts). I ordered a replacement that was advertised as a replacement for the part # on the old transformer. It looks like the right part. The leads have a C, R, Y, W, G, which was the way the old one was marked. I made a diagram of the wiring before I put in the new one; even took a picture of it for reference. I'm convinced I put it in with the same connections as the old one, but here are my weird blower results:
1. The blower works with the thermostat set to Fan->auto and System->cool, but opposite from what you would expect: when the temp is set to a high temp (fan should be off), it turns on! When set to a low temp (should be on) it turns off!
2. When the thermostat is set to System->Off, the blower runs!
3. When the thermostat is set to System->Heat, the blower always runs, makes no difference what temp the thermostat is set to.
4. When set to Fan->On, the blower is off.
Can someone tell me what the !@<hidden>#$% is happening. I have compared the wiring umpteen times, comparing the old to the new, and I'm convince I have them the same.

In case it helps, here's the way it is (and was) wired:
1. C- Red from outside unit plus beige to furnace.
2. Y- Did not and does not have a connection.
3. G- Green wire from thermostat.
4. R- Red wire from thermostat.
5. W- White wire from thermostat plus a black wire to what looks like a fan temp part (relay ?).

Any help would be appreciated.