Nissan Repair: 92 Pathfinder Electricle Problems?, max volts, fuel pump relay

Question
I have a 1992 Nissan Pathfinder, Power everything. 3.0 V6, 5 Speed. 4 wd, and. its got some electricle problems, the Rear window wiper will come on for no reason out of the blue, then go  off, come back on, theres no Tail Lights, but theres Head Lights, and Theres NO DAsh Lights, but the Engine Light comes on n off, so does the brake light, the Tachometer will go to 5,000 RPM and stay there, The Voltage Meter goes Up and Down from like 11- Max Volts and get stuck there, and the Fuel pump doesnt work, unless u HOt wire the pump from the batter to the Positive side of the pump. someone thinks its the ECM. but that controls the engine. any Ideas?  

Answer
Jerry,

You have several different problems that are electrical but not connected.  Replace the fuel pump relay for starters and it should work.  Replace the master switch on the column and the tail lights should work again.  The dash lights are out because the dimmer switch on the dash needs to be replaced.  The alternator should be checked since it appears that it is going to max charge which will burn up things in the vehicle.  14.2 volts should be the max output and that should be present at off idle.  The instrument cluster should be taken out and the contacts where it connects to the harness should be cleaned with a number 2 pencil eraser.  Just scrub the terminals on both the cluster and the harness and put it back in.  If the tach goes from zero to max the resistor in the circuit is defective.  Email me back with your corrections and I will let you know if there are other solutions you might need.