Air conditioner is decent, but Dehumidifier is a mystery

I have owned this thing since early summer. It worked well enough in our master bedroom as an air conditioner. It never got the room "cold", but it did drop the temperature enough to make it comfortable for sleeping. However, the dehumidifier function is a mystery to me. I planned to use this thing in my garage during the winter months to help keep everything dry (I live in the Pacific Northwest and it rains constantly over winter). I have left it running for about 12 hours in my garage and I check the water trap and it's completely dry. This is during a very wet week with lots of rain, so I can only assume this unit isn't actually grabbing the moisture out of the air like it should. The instructions in the manual are not consistent and I'm not sure if the unit isn't working right, or if I don't have it setup how it wants. The dehumidifier mode is called out a few times in the manual, notably on page 13 and 15. However, there are contradictions on how to setup the unit. Pg 13 says to use the air exhaust hose, but then pg 15 says not to use it. Pg 13 doesn't require the drain hose, but pg 15 does. This isn't the worst manual I've ever seen, but I hate seeing inconsistencies like this and I can't seem to get any firm information on exactly how this thing should be set up to get it to work right in Dehumidifier mode.

###

