I removed the Japanese radio, fitted an android screen in its place, all well and good up to now,

refitted the head unit, but now the AC doesn't come on unless its on dehumid for front screen, also the temp buttons will go up but not down.

any ideas where I went wrong, apart from doing it myself LOL

any ideas will be gratefully accepted.

Sounds like the A/C panel connectors are not fully home into the fascia.