Re: trim
That electric motor is a dual polarity motor, meaning that if it works in either direction, it is okay.
In DOWN mode... does the electric motor run, OR is it a case that all you hear is a click and nothing happens, OR is it that simply nothing happens... no click, nothing?
If a click and nothing happens... reverse the relays (the clicking items). If the problem reverses (down but no up), a relay went bad.
If absolutely nothing... check for voltage at the down wire of the PTT switch when in the DOWN mode. (faulty switch?)