I removed all of my a/c components and bypassed my heater core because it was so badly rotted out. I had purchased a brand new blower motor previous to doing this but could not get it to work. Since then, I have not had it hooked up. Recently, due to the cold weather I tried to hook it back up again. Still nothing. One morning, I had my defrost on, because having the vents in that position does let some air in to clear up the windows. I pulled into the gas station, and I heard the motor whir on. I unfortunately began to mess with it and eventually it stopped working. The only position it did work in was defrost. This has happened twice more. No explanation I can think of except maybe I kicked the wires in the fuse panel or hit a bump right. When I put the defrost on, it makes a clicking noise down in the fuse panel. I havent been able to pinpoint the culprit of this noise yet, however, and all the fuses are fine. Does anyone know whats wrong or have any suggestions as to what could be the reason for this bad wiring?

it might not be the wiring .. it could be the computer chip that governs the whole system..

I know for a fact that the mid to late 70's used a command module for the HVAC control. The one in my 1976 Coupe Deville cooked itself while under warranty and was replaced free of charge. Six years later it crapped the bed again, and would kick on the defrost cycle only. It eventually killed the clutch on the A/C compressor. I quickly learned that the repair would have been far less than $900 1983 dollars if I had addressed the problem before it took out the compressor.

That is one way how we become older and wiser. LOL!