Hey all new to the forum, just brought my nav runs like a dream. Had a hot summer here in aus now the rains hitting cars fogging up like it’s getting hotboxed lol. Heater blowing out cold air . Checked engine and walla! No hoses connected to the brass/copper fittings in the firewall to heater core .. needing to fix hopefully ripping the dash out is not the fix . I found the by pass .question is I don’t know why it’s by pass previous owner never mentioned . Can I hook it all back up an if problems just by pass it again