Best place to start might be getting a hold of a electrical diagram, I think there was a link to them on this forum. Do you have a voltmeter? You might have to pull the dash apart and find where the problem area is.
Sometimes there is an inline fuse. Check with a voltmeter to see if you are getting anything. if you aren't you are going to have to tear it apart and find where the problem is by seeing where the current stops. Something must be stopping it from getting to the lighter port.