Tach does not work 1987 GL on 1990 Ford Escort

Tach does not work 1987 GL is the intrument panel voltage regulator at issue or a bad tach unit? how to tell which? \\smile//

by in Ritzville, WA on October 22, 2010
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1 answer 1 comment
ANSWER by , October 22, 2010
The instrument voltage regulator is for the temp and fuel gauges, the tachometer works off a different circuit. If your temp and gas gauge work then the voltage regulator must be OK. The tach works on a different principle than the temp and gas gauges. The tach unit could be faulty or ther could be a problem with the tach signal from the engine. The DrkGrn/Yel wire at the ignition coil is where the tach sigmal originates.
COMMENT by , October 22, 2010
Temp & gas work fine; will try to check the DrkGrn/Yel wire. is there a way to use, say a 9V battery and tap the DrkGrn/Yel wire to see if the tach needle bounces? or to wire a circuit to simulate a 500 to-some few thousand rpm 'fake?' signal to test the tach? [back when I used to make one of those...