Where does the lead wire tachometer go on to coil And what color is need be for a 1989 1500 Chevy truck?

The lead wire for a tachometer on a 1989 Chevy 1500's coil usually connects to the negative (-) side of the coil. However, there's no single guaranteed color code. GM's wiring practices varied even within the same model year.

To find the correct wire, you need to:

1. Consult a wiring diagram: A wiring diagram specific to your 1989 Chevy 1500 1500's engine (the engine code is crucial!) is your best bet. These diagrams show wire colors and locations. You can find these diagrams in a repair manual (Haynes, Chilton, or a factory service manual) or sometimes online through forums dedicated to your truck.

2. Use a multimeter: With the engine off, probe the wires connected to the coil using a multimeter set to the DC voltage setting. The tachometer wire is the one that shows a pulsed voltage when you crank the engine. This is a more reliable method than relying on color codes alone. Always be careful when working with automotive electrical systems.

3. Test the tachometer connection: After identifying what you believe is the correct wire, connect the tachometer lead. Start the engine and see if the tachometer works correctly. If not, double-check your work. Incorrect connection could damage your tachometer or other components.

In short: Don't rely on color codes alone. Use a wiring diagram and a multimeter to ensure you connect the tachometer to the correct pulsed signal at the negative side of the ignition coil.