It is hard to imagine the layout of what you describe. So there is an AC Evaporator somewhere near/above the bathroom sink, such that the condensate pipe is routed under the sink and out to daylight? Where the P-trap is downstream of your bathroom, so it is now backing up and leaking through some fitting under your sink?Hello My ac drain pie is leaking under my bathroom sink. I know it's clogged. How do I unclog it? Started leaking yesterday but it's leaking a lot. Need a DIY fix.