Nissan Repair: Tachometer, nissan maxima, signal wire

Question
I have a 1995 Nissan Maxima.
Drove it home from the dealer (as-is purchase);
used the A/C, the tachometer started malfunctioning - it just keeps rising to the max and only resets once I turn the engine off.
I have not used the A/C since, and the tachometer
still is not functioning right.

What could be causing this, and what's the proper way to fix it? Thanks for your advise.


Answer
Jox,

If the tach goes to max every time the engine is on then the tach is defective or the wire feeding signal to the tach is defective.  If the car runs fine I cannot see the distributor as being defective on this one.  I would start with the signal wire for the tach at the coil and work my way back to the tach.  All other gauges work fine?  If so, and the wire is not grounded then I would go to a wrecking yard and get a used replacement.