Either you did something wrong (cant imagine how, worlds easiest mod) or you're having completely unrelated things go wrong out of pure coincidence.When I did it, I originally grounded to the chassis where the battery ground leads to... after about a week my battery bursted with battery acid everywhere.
I thus re-wired it to the negative battery terminal. Then I noticed that my a/c light flickers and wanes in and out at times and sometimes turns off by itself... I did notice a difference when I first put it on, but the symptoms I get may not be worth it for me. I've had it on for over a year now.
Connecting your TB to your chassis CANNOT cause any of the things you're describing.