We have the same year 31 CB. As mentioned by someone else, there is a toggle switch to the right of the main helm that has to be in the on position to have the remote thruster to work. There is one more thing I would suggest you check. I replace the remote batteries every season and when you look at the interior of the remote to see which direction the batteries should face, you see a + sign. That made me assume that the battery should face + side down. I did that and the remote would not turn on. I reopened the remote and inserted the batteries with the + plus side facing up. It worked properly with no issues. I found the battery polarity sign inside the remote misleading into making me think that the positive had to be facing down, when in fact the positive has to be up. I hope this helps.
Sonny