New here, decided to join after I saw some good information available from the users here!

So... I recently purchased a 2010 Ford F250SD XL, with only 13,000 miles on it. I use it for work, and I pull trailers. It did not have the TBC module or the upfitter switches on the dash, just the coin and mail holder. Ford dealer wanted $600 installed for the TBC. I said no thanks and got a like new one off eBay that was "supposed" to have been tested working. I got a bank of upfitter switches too to fill the rest of the hole the coin holder left. The harness for the TBC was plugged into the back of the coin holder, easily got it plugged into my new TBC module and installed. I turned the truck on, all the display lights on the TBC on the display on the left side of it came on for initial startup, then went off. I pressed the gain switch and the + and - buttons, and nothing would show up on the screen. No options on the instrument panel were available either. I read online that the module had to be calibrated to the truck. I took the truck to the Ford dealer, they calibrated it, tested it, and said there was no output from the module, but wanted way too much to diagnose it. I hooked my truck up to a trailer and drove around with it. Nothing ever lit up on the module, no matter what I did with the gain increase slider or buttons, no gain or lights ever came on in the instrument panel, or the TBC. However, anytime I pressed the TBC slider, the brake lights on my truck and trailer came on fine. So I know it's connected and communicating to some extent. I read that you have to modify or replace the master brake cylinder or add a pressure transducer on 2010 and lower models to make the TBC work. Is that true? Do I have a bad module maybe, and how can I test it to find out? If it is bad, I can get my money back and get another. I drove a 2008 F250 once, and the TBC lit up and showed the gain anytime you pressed the slider, even when a trailer wasn't connected, so it makes me suspicious of mine because it doesn't light up at all except at startup or turning the key to on. Any ideas? I'm about to just take it to my mechanic that does all my trailer wiring and tow package installation on my work trucks and have him figure it out. I need to know if this TBC module is bad first as I want to buy one on my own from a third party, not ready to pay $300+ for a new one.

Help!