Nissan Repair: 1994 nissan pathfinder, nissan pathfinder, electrical diagnosis

Question
the pathfinder was dead because it was sitting for about a week and a 1/2.  My sister went to jump it with our mother's 06 hyundai sonata.  she hooked up the pathfinder first then when she went to hook up the sonata she accidentally put the positive cable on the negative terminal and the negative cable on the positive terminal.  the battery started to smoke on the pathfinder.  she turned the car off and when she hooked the cables up the correct way the pathfinder started but nothing electrical would work such as the radio, door locks, windows, blower motor, etc. what should i check first or should i just replace the computer?

Answer
Jamie,

You are in luck since the vehicle started.  That means the computer is fine.  The other things are an issue.  Reversal of the calbes can cook the computer, but in your case you are fine.  But, on the other stuff you need to check the master fuse at the positive battery cable.  There are fuses on the positive terminal.  If those check good then go to the fuse box and check the fuses to what does not work.  Most everything should be just a fuse.  But, the radio might need to be pulled and repaired.  Check each fuse and email me back with what you find.  Also, now that the Pathfinder will run go to Autozone or Checker and get a free electrical diagnosis to see if the battery is defective or the alternator is not putting out.  That was the original problem since it was dead to start with.  Remember that new vehicles loose about 1 percent of battery charge for every day they are not started and run.  A week and a half should not have caused the vehicle not to start.