Radiator fan broke, was replaced with ebay part, now runs on high all the time

2006 Mazda Tribute 6.0 (200,000 miles yikes, I know)

Few months ago I was waiting a red light when all of a sudden I heard a loud metal clunking sound and my car began shaking. I pulled over, called the bf for help, and he realized the radiator fan had broke. We ordered a replacement part from ebay (maybe not the best choice?) and ever since he installed it, the radiator fan only runs on high speed, and whenever it kicks on (which is very often) it makes my lights dim and makes the car feel like it wants to die. There is a third connection on the new radiator fan that is open and not connected to anything (at least we couldn't find a loose hose)

A month or two later, my car died as I was driving. We checked out the battery, and it was dead, so it was replaced (only 2 years old). Then, few weeks later, the alternator died. Was replaced. Few weeks later, we decided to change the thermostat & water pump to see if that would take care of the radiator fan on high problem, but nope it didn't... it made it worse. It made the radiator fan stay stuck on high ALL THE TIME.

We took it to a dealer finally, and after 2 days, they only were able to determine codes "faulty control module." I needed my car for work, so they said once I take it back, their next course of action would be to check the fan control module.

We checked the relays and fuses, and they seem to be okay.

PLEASE PLEASE PLEASE does anyone have any thoughts on this???