is the ahhc module showing any error codes. if you look at the red light after you try to run it it will have short flashes and long flashes your book should tell you what code means what. hope this helps.
I installed a new ltm the other day and it did the same as yours. No error codes,everything checked ok. Finally adjusted tilt gain from 2 to 5 flashes and it worked fine.Never had to change that before.BTW,830CH.
did you adjust lateral tilt gainIJ did you go through the calibration sequence after installing your headerIJ we often have to do this when reattatching header when going from field to field. make sure you follow procedure in operators book.