1997 Honda Accord Blower motor only blows fuses

My blower quit working about four months ago. I have replaced the blower motor, the resistor pack, the relay, the switch, and of course, the fuse. I can replace the fuse, start the car, and the blower works fine. It will keep working as long as the engine is just idling; it even keeps working in reverse. But when I put the car in drive and give it a little gas, it blows the fuse. I have tried to trace the wires as best I can looking for a short, but haven't found one yet. Please help me - I'm going crazy trying to figure this out!