how do you test to see if it is sending signal to tach?? I have a unknown Tach as to good/junk. You turn switch on it zero's out. Does not read engine rpm with engine running. wire has continuity. Bob
Elect Gru's; At 1000rpm should the wire read about 12 Volt VAC at 60 hz????
tach is good. Now to check K1 pin at ecm