Luckily i met a honest ac shop with otai pomen.

Before CNY went to service Nissan Grand Livina ac, the car come with rear passenger ac too but power by only single blower so the ac wind is not strong even for front side. The pomen help me clean my cooling coil using machine without disassemble dashboard and advice me to remove ac cabin filter but remained the cover if wanted to feel stronger wind. He even got camera to check how dirty is the cooling coil and show me video of before and after cleaning cooling coil. He told me filter is safe to remove as long i service ac on time.

During CNY the AC wind suddenly become very low, so i bring my car to another ac shop for checking. The pomen just making assumption my cooling coil is dirty, have to disassemble dashboard to clean it. I told him i just service my ac not too long ago, impossible so fast cooling coil clogged up.

I decided to went back to the first workshop service my car ac. Without much checking he told me is due to cabin filter box didnt sealed properly causes ac wind leakage, he just help me sealed the cabin filter box with masking tape and that solve the issue, until now the ac is working cool and fine.