Remote fob won't lock or unlock doors

I managed to lock myself out of my 2003 RSX yesterday when I took only the fob with me and used it to lock the car, only to return an hour later and have it not work. It was raining, too. :mad:

I've done some searching and reading on this helpful forum and have a guess, but I would still value some confirmation from you knowledgable folks.

• Remote won't lock or unlock doors and hatch
• Remote will set off Panic Mode and show a red light when pressed
• I tried changing the battery in the remote -- no difference
• The interior door locks will still lock/unlock the doors
• I had a prior issue on the driver's side door where the lock would not lock/unlock without a key. That was fixed over a year ago (but I don't recally what it was)
• I've read a handful of posts here that reference the actuator as the likely culprit

My questions are:

• Is it likely to be the actuator?
• If so, how do I know which one? (Driver vs. Passenger side)
• If I'm not overly inclined to DIY, is it worth just taking to my mechanic to get it fixed?

Thanks so much in advance!

Remote fob won't lock or unlock doors