wrote in message
ups.com...
Luo, thank you for the reply. I have just installed a new battery
(before tach problem began). It is still a 12 volt battery but has
more cranking amps than the previous battery. I do see on the volt
meter that when the engine is running that the volts are at 15 volts.

this is not normal. 15 volts is really too much,
you will fry more things than tachometers.
check the alternator/regulator

and check your voltmeter