Nissan Repair: 95 Pathfinder Problems, rear brakes, rear abs

Question
Hello,   
I have a 95 Pathfinder XE that has 2 problems. The RPM Gauge doesnt work, it just jumps all around when the truck is running. Do you know where the RPM sensor is? Maybe a short or bad sensor?   And also the ABS light is on. It has been on since i bought the truck. i think the rear brakes are in need of replacing, could that cause the rear ABS to fail. If i unplug the ABS fuse for 1 minute then put it back in, the light goes out until i press the brake pedal. Is there anything i can look for on either of my problems?     Thanks!!

Answer
Joe,

The tach runs off the coil that feeds current to it.  If the tach is jumping all over I would think the tach is defective.  Go to the wrecking yard for this.  The ABS needs to be checked out.  What I always do it bleed the system with Ford High Performance Brake Fluid.  Bleed all four wheels one at a time until the fluid is clear.  Then, reset the light as you did before.  If the light comes back on check all four wheels for the sensors and make sure that they are not broken or the wires are not cut leading to them.  Lastly, it will be the ABS unit if everything else checks good.  But, usually the changing of the brake fluid does the trick.  Now, I have seen the wires torn out on four wheel drives from driving off road and they are pretty easy to solder back and seal.