I have a 08 LX with nearly 300k km.
These switches and buttons didn’t work when I bought it last year. Anyone knows where and how I should be checking it out? Thanks in advance.

 

Most likely cause is previous owner spilled coffee, blotted up what he could see, but did not remove the cover and mop up the rest.

You need to gain access as there are many cables and connectors that can get fouled up with liquid...soft drinks are the worst. Outside panels need to be removed and the switches are normally snapped in below the outside panels.

 

Thank you, @hankinid

I checked all the fuses and changed some bad ones, it didn't help.

As you said, it is really bad if it was polluted by drinks like coffee, the whole switch-set assembly needs to be replaced as it has circuits inside.

 

Unfortunately that's the fix if de-mating, cleaning, and re-mating the connectors doesn't work.

 

Update:
I just got to know that the third fuse panel is on the passenger's side that I've not checked, AND, the AHC and other functions are affected directly by the fuses here.