Hi Mike,
I posted about my 05 overheating last week on the forum and have not had time to look into it until today. This is what i found, I unplugged the harness going to the fan and made a switch like you described in a post to me and the fan will run on low and high. so i heated the engine up to running temp and checked the other side of the harness unplugged from the fan and found fire to both hot wires with the ground (black) wire, then hooked harness back together and fan will not work, why am i loosing power when i hook the harness together? Do you think its the fan module and where is it located, can i test it?