sounds like the 12v DC auto reset breaker between the battery and the TT wiring is bad
follow the black wire from the tt battery, it should go to a little silver box with (2) connections on it , just so you know ..the Black wire is the Positive/plus and the white is the Negative/ground..do not hook up battery backwards
goto the auto parts store and get a NEW One size 40 amps
as a test you can move one wire from one terminal onto the other terminal , if the thermal breaker is bad and everything else is OK power will come back on
