How do you diagnose and fix the speedometer that only works intermittently on a 1996 Nissan truck?

Hi There, On my 1995 Nissan Pick-up, The speedometer as well as the tachometer would intermittenly stop working. Sometimes one would work then the other would stop working, sometimes both stopped working at the same time. I never knew when it would happen. Then, at 90,000 miles, the Check Engine light came on and everything worked GREAT. It turns out that the wire that sets off the Check Engine light was shroting out causing the problems. It was fixed today for a cost of $160.65. It worked for me, I hope that it works for you.

Good Luck!