I have a La Crosse charger too, and the Current button never worked very well. When I researched it, I found that lots of people have problems with the buttons and that the buttons aren't constructed very well. I'd return it and when you get a replacement, make sure everything works perfectly before your warranty expires. Buttons seem to work less and less over time.
I had a few days left to "return/replace" via Amazon, so I did that. Very easy process. I'll get the new one before the old one must be returned, so I'll try it out first. I was hoping that maybe it was something I was doing wrong, but I read the manual, held the mode button for a while (until display blinked meaning the charge settings we "set" for that battery bay), but nothing. I watched YouTube too (found a really bad one for this charger), but what those folks could do, mine would not. I guess I just got a bad charger. The other buttons do work, so I can change the charge rate and view the various settings once it's begun its process, but just cannot change the mode so that it can Charge, Discharge/Refresh, Charge/Test, etc.