GM-GMC: van wont start, chevy g20, conversion van

Question
Hello, I have a 86 Chevy G20 conversion van, I recentley had a tune up, I have installed a brand new battery, my problem is that it will not start. It was running fine 2 weeks ago and now it won't start. I was wondering if you could tell me what might be causing this, It had a handicap lift of which I had removed, but the black cable wire that was connect to this unit is still connect to the 2nd battery that is in the van and the end that was connected to the unit is just taped off, my question is could this be draining my battery so it won't start?

Answer
Is the van a diesel?  From your description of a tune-up, I would guess that it is not a diesel.

Where is the second battery located?  The taped-off description would indicate that the battery is no longer connected to the vehicle in such a way that it would charge or discharge, but that may be true (I cannot see it, so I cannot be sure).

Your description seems to indicate that the battery is being drained and will not crank the engine.  If that is correct, you will need to find out where the battery drain is coming from.  It is possible that the handicap lift was incorrectly removed and perhaps you should take the vehicle back to the shop where the lift was removed for them to fix the problem.