It is also quite possible that the fans and windshield motors all generate RFI (Radio Frequency Interfearence) and can easily tear up a an already finnieky DTV signal. The interfearence is being radiated out the power lines of the brushed motors, and being picked up by the antenna. This is also common with many LED lamp regulators. Turn on porch light, good by TV.
"Rewiring" will not necessarily fix this unless you install RFI filters: .01uf caps and ferrite chokes.
If, when the motors come on, the picture quickly freezes, then goes to black, that's a good sign this is the cause.
(Edit: iPad "spelling correction")