installing a tachometer

[KenWittlief]

Originally Posted by greencactus3

i have everything connected except for the positive power. i need a wire that has current only when the key is in the "on" position. dont see why it cant be on with accessories but yea. its what the manual says. whats an easy wire i can find for that? i have a 98 s10 if it helps. and jeez feeding wires through the firewall is annoying.

usually the fuse box on on the inside of the cab. If you have a voltmeter, or even a 12V light on a jumper wire, probe the fuse box with the key off, to see which fuses are dead. A tach will draw almost nothing, so you should be able to jumper it into any fuse that is only live when the key is on.

On most cars, the radio power is an obvious choice for what you are doing.