When I'm in insert mode, I sometimes want to be able to move around without using the arrow keys, and without having to go back into normal mode. So in my vimrc I've set up key bindings to do this:

imap <C-l> <right>
imap <C-h> <left>
imap <C-k> <up>
imap <C-j> <down>

But for some odd reason the only one that doesn't work is the last one, . Doing this in insert mode just gives no response. I'm wondering why this might be, and I just don't know where to even begin looking for the problem. It doesn't appear to be mapped to anything since nothing happens when I do it, whether I'm in the terminal or in gvim. Any pointers would be great! Thanks!