speedometer help

[redline racer510]

I baught a 1990 240sx that has a speedometer issue. Most of the time it doesnt work but once in a while it kust turns on for a few minutes then it cuts Off.How can i diagnose the problem??:-/

[g6civcx]

S13 speedo has been known to fail intermittently. Swap in a known good.

If that doesn't fix it then check your VSS wiring from the gearbox for shorts.