How to handle disagreement between collaborators on licensing academic code? A group of students including myself have developed a certain program/algorithm. I as the main coder behind this group have provided 95% of all the actual code. The other two involved parties have given 4% and 1% of the code each.

The code was created in an academic environment for a paper, but the actual algorithm has applications not limited to the scope of what was worked on during the duration of our work together.

I wish to release the code as open-source as does the other party who contributed 4%, as it has other applications, and potential uses, and we don't want to limit its use. 

The problem is that the 1% is adamant about not releasing any code and keeping it. He will not listen to reason. 

Can we just use a majority vote to decide this? Do I as the main coder have more say than the other two? We do not want to get any external parties(ie., lawyers) involved.

This is not a question about the benefits of various licenses; we know what each licence does. As Simon statrs: "it's about team dynamics, within academia, where collaborators disagree about whether to release the code at all." Two of us want to release. One of us does not. How do we proceed in such a situation?
If that other 1% of the code isn't anything special (which I'll assume is the case since your question would have otherwise made a point of it), tell the other coder that if he is going to be adamant about it, it will force you guys to rewrite the code, and he might not get any credit at all.  See how he "likes them apples". 

Otherwise, you might search for his reasons (is he hoping to commercialize it?) and find a license that he's amenable to.  There are many licenses that support a basic idea of "open source".

I'd opine that you can't legally use his work without his consent, but you can rewrite it.  But if he made new IP (that is new thoughts/techniques that no one has coded before) encoded in that 1%, you will probably have to negotiate those rights. 

Note that this opinion, is applicable within the academic community where a "shared intellectual commons" has been fairly active for centuries.  It may not be appropriate policy for commercial entities.