Troubleshoot a tach..

[Bryce18parker]

I have and 89 sunsetter with no tach reading. 

Is there a way to tell if it's the gauge that is bad ?(similiar to testing the fuel gauge?)

Thanks!

[Bryce18parker]

Or a thread that already covers this??

[justgary]

Is your system a Medallion gauge set, or old skool analog?

If it's old skool, two obvious answers come to mind... try another tach to see if it works (your local dealer may have an old one sitting on the junk shelf that you can borrow, or use an oscilloscope (or just an AC voltmeter) to see if you are getting pulses.

If it's Medallion, try searching this forum.

[Woodski]

My guess an older basic tach for an 89 era boat.  You should be able to simply connect a known good tach to the coil then to the actual boat tach connection to confirm signal is getting to tach.  Should be a basic coil to tach and tach to ground setup.