My PF IR remote led indication light is constantly on after I put in new batteries. It stay on without me touching anything. A quick check with my phone camera showed that the IR emitter is emitting. It sends signals to the receiver which activates the motor even when the channel on the remote and receiver are not matching. Is there anything I can do other than buying a new remote?
The Lego Company is usually very good about replacing broken and defective parts for free. In the case of expensive electronic parts such as this, in my experience, they will sometimes request you send them the broken/defective one. If this is the case, they will make it easy for you and send everything you need to do so with your replacement. Because this part is still made/sold, there is a good chance they will make it right.
If this solution doesn't work out for you then you could try fixing it. I would recommend taking it apart, if you have the tools, and look for any obvious signs of contaminants, over-heating, breakage, etc. If there aren't any obvious issues then try storing the electronics in a bag of rice for a couple days to absorb any moisture in them. If none of these things work then you are probably going to need a new one.