Nissan Repair: 1994 nissan altima power window/door problem, nissan altima gxe, 1994 nissan altima gxe

Question
Dear Mr. Sudderth
I have a 1994 Nissan altima GXE 4dr sedan, the battery fuse under the hood was burned and also two electical part fuses were burned on the fuse panel. I don't know what is the reason to casue this. All the power window stop working after I replaced all the bad fuses. I only can lock all the doors through the swith on the driver side, but the none of the windows can be scrolled down or up through the switch on the door, also the unlock switch on the driver side isn't working anymore neither.
Another problem is that the dash board light is not working anymore after I replaced the manufacture radio with an MP3 player. I thought I might have made some bad wiring conncetion, so I put back the old manufacture radio, still the dash board light is no longer working. I brought this car to a mechanic guy to check out the dash board light, he said all the light balls are still good.
Would you please try to help me figuring out these problems?

Thanks a lot

Answer
Sara,

You have a dead short somewhere in the car.  That is, something is grounded to the body of the car.  The only time I have seen this on your model was when a converter, under the car, got so hot it melted the electrical wiring under the driver's seat to the floor pan.  Once I found where the carpet was crisp from the heat I pulled it up to find the wiring cooked to the floor pan.  I corrected the problem, replaced the converter and the fuses and all started working again.

On the instrument lights subject there are a few possibilities.  If there was an aftermarket unit installed incorretly and Nissan makes it easy with their circuits that show to be ground one minute just to turn to power when the key is turned on could be the cause.  I would think the master switch or dimmer switch was overloaded and cooked.  So, you will have to replace one or both depending on which was overloaded enough to burn up the contacts inside.  My personal bet is the headlight switch since it is the one with contacts in it and the dimmer for the dash is nothing more than a variable resistor.