I am putting a tachometer in and i need a key-on voltage source. What would be the best way to hook it up? Would the BAT post of the starter relay work or do i need something else? Any info would be helpful

Thanks
Robert

 

Are you looking for an inside or outside source? The btt term of the relay will give you power all the time. Why not run off the "run" term of the ignition?

 

T off of one the fuses on the fuse pannel.

Use a volt meter or test light to find out which ones are Key-on (I think they all are excpt 1)

-Gun

 

Run a wire from the coil terminal. I believe positive side will work when key is on.

 

ok thanks for your help it is greatly appericated....

 

If you use the coil terminal you may not get 12 volts if there is a resistor in series with the coil.

I ran mine off the radio power wire, it has an extra socket for a bullit connector on the 65's.

 

What about the starter relay? which post will work for key-on voltage?

 

I just installed a warm air choke using the reverse light wire. it is a black and red wire. there are two one only is hot when in reverse the other is always hot when the key is on. check with a voltmeter. the nice thing about this wire is it only draws power away form something else when in reverse. and it is always 12 volts.

 

Look on the back of the ignition switch. There is a center post on the switch, usually not used for anything. Test it-I think you'll find it's a 12 volt switched source. The only downside is that it's unfused, to be safe you should put a fuse in the line you have just tapped from the switchbefore it reaches your tach.I'm using it for my aftermarket gauges lights on my 67 F/B. it's been fine for more than one year.
Hope that helps,
Jay67fast

 

There will be an "I" above the post that will work with key-on. The other post will have a "S"