Examine the sections of the harness that you “cut down” . Are there any ground connections that you removed. Or, did you perhaps not reattach a connection to the body shell? You are giving me scant information to work with.
Also, if you deleted any circuit from the instrument cluster, even if it was only pulling out that annoying warning buzzer from the inoperative airbag system or a warning lamp for a catalyst malfunction warning, you may have tinkered or fettled a bit too much. Modern vehicles have passive restraint systems that are not so passive when the systems malfunction warning lamp features are removed.