Hi codeo, don't forget what you're talking about is the PACK, that contains an air cycle machine and a hot air bypass valve that mixes cold ACM output with hot engine bleed to get required temp. The ACM can only output freezing air, there is no control of it.
The trim air valve you mention is downstream of the pack to give an option of different temperatures in two different cabin zones, but you need the pack to work properly for this i.e. ACM mixing its cold output with bypass air!