Nissan Repair: 91 Nissan Maxima Power Drain, nissan maxima, haynes manual

Question
My Nissan maxima has been giving me continuous problems with power drain issues. I've replaced the battery (yellow top)and the alternator recently. It worked for one nite, and the next morning my power was completely drained. Since I've purchased the maxima I have enhanced my sound system and also installed an alarm system. I even took it back to the people who installed everything and they assured me that everything was cool on their wiring. However, the alarm will not shut off now, i had to disconnect to get it to shut off. I know that's an issue on their end, but on my end apparently there are 3 wires that are going to the positive connection on the battery, one of which is apparently used to send power to the alternator.
According to Nissan, these wires aren't suppose to be there, however the part that they were trying to sell me has to plugs on both ends. the problem is that, what am i suppose to plug into the other end? It seems like it needs a wire to be rigged to the other end to connect to the battery. I'm going crazy, and no one seems to have any answers, including Nissan. They just want to charge me 89.50 for an hour, when i know that it surely would only take the at most 15 seconds.. Please offer as many suggestions as you can think off..lol

Answer
Andrae,

I would think the alternator wire is not connected and that you are running on the battery and that is what is killing your car.  I would purchase a Haynes Manual and follow the wiring diagram in the back of the book and make sure the wire that connects to the battery is also connected to the back of the alternator where it will trigger the charging to begin when the vehicle is turned on.  Also, before you spend any money or do anything, go to Autozone or Checker and have them perform a free electrical inspection.  They will being out a tester and check your charging system while the vehicle is running so you will know for sure if you have a charging issue and need to route a new wire.  Also, check the master fuses on the positive battery cable.