156 Aircon drain
Just had to tackle this problem myself, reading the previous posts was a great help, but there is an easier way to find and access the drain (RHD) - remove the battery and battery tray, much easier to then get your arm in. The drain is just to the right of the heater water pipes against the bulkhead. You'll feel the bottom of the rubber bellows protruding from the insulation. Remove a small portion of the insulation, just bigger than the bellows, it tears quite easily. I found there was no dirt etc blocking the drain (rodded it with a long cable tie), if you push your finger up the bellows you will feel the end of the rubber drain pipe. Problem with mine was the end of this short drain pipe was hard up against the front face of the bellows, so obviously with time, heat, water it must have almost "fused" itself together. I slit the front of the bellows to just below the drain pipe, then by pushing my finger up to part the front of the bellows from the drainpipe I inserted a small rubber hose into the end of the drainpipe, about 10 - 20mm deep. When you release the bellows again it holds this hose in place pretty firmly. Lead the hose down past the steering rack and between the rack and hydraulic pipes, this holds it from flapping around. Cut it off just below the steering rack where I could see it below the car. Ran the engine with aircon on full for a couple of minutes and - bingo, condensate running out. Then closed the slit bellows with a tube puncture patch to prevent splash, dirt etc.