ok i am installing my tach on my 89 f150 4.9 L EFI it says to conect a wire to the negetive side of the ignition coil, but i am having problems finding it, and my last question is, i am also suppose to connect a wire to the + ignition switch and i was wondering if it would be ok if i just hooked it up to the constant power with a fuse and all, or should i try and connect it to the switch.

thank you for your help.

 

Book says coil negative is dark green with a yellow stripe. You don't have to go TO the ignition switch, just to something that comes on when you turn on the key.