I work for a TD (member of the Irish Parliament). If you write him, you’ll usually get a letter back*, although it’s likely to have been written by me or his other assistant rather than by himself. Unless it concerns a specific matter within his constituency - say a dangerous road or a school issue - he probably won’t ever even read it himself.
As to whether it will affect how he votes on a bill, probably not, but that’s because we’re in a parliamentary system and all our elected reps have to cast their votes in line with party policy. But on matters that strongly affect his constituency, it may well affect how he uses his influence within the party to shape party policy on the subject.
Ino, if the rep isn’t on that Committee, they probably really can’t do anything yet.
*I say “usually” because there are some complete nutters we think it’s best not to encourage by replying to. If you aren’t a nutter and you don’t get a reply, we lost your letter. It happens. Sorry.