Stopped making ice. Black stuff coming out on ice

First I removed the (3) screws holding the unit to the side of freezer wall with a nutdriver. Then I disconnect the Harness from the back of the freezer. You have to work the Harness off connector because it was very tight. The Unit came with the correct harness installed so I reconnected the harness to the Freezer and replaced the (3) screws. I had ice in about 2.5 hours.