My fuse didn't look burned through, but had melted enough for the connection to be intermittent. They're cheap, just get another one to eliminate that as a problem. The overdrive system is pretty reliable, so the only time you should have trouble is when the Overdrive solenoid is not getting power. Clean all your connections, of course and check for continuity in your wires. Did you disturb the cable which engages the OD? If so, it may still freewheel, but not engage enough to activate the switch at the transmission.