Hey guys. I'm in the process of installing an aftermarket tachometer in my 90 CRX Si. I have everything wired up except for the last wire which the instructions calls " + 12 volts keyed ignition (main gauge power) ". My question is which wire off the ignition do I connect this to?

 

Hook it to any 12v line that has power when the key is on, but doesn't with the key off.

 

This is correct. There is an empty one under the dash in the fuse panel iirc. Check it with a volt meter to see if it gets power when the key is on but not otherwise. Then wire it in there with a fuse. Easy.

 

So you guys are referring to what would be considered a 12v accessory?

 

Check your fuse panel under the dash. There are a couple empty spots that you can plug into for power.
You can use a meter or just plug your device in to find a slot that only powers up when you turn the key.

Just crimp on a blade terminal to the power wire and plug into the fuse panel.


You can even make it a fused circuit with something like this

 

Appreciate the suggestions guys. However in this case I specifically am wanting to connect at the ignition cylinder. So again, which wire?

 

Hmm, sorry, not sure which wire, but I do have a question. Why an aftermarket tach? Even if you want higher rpm, EF's did have a 9000+ factory cluster to be sourced out

 

Deetz- the ukdm cluster was an option for a while but the immense prices kept me away. I didnt want to do the jdm cluster either for similar reasons plus the wiring changes needed. Also, I have a one-off customized CRX Si cluster that a friend had made for me who passed away several years ago so in the end i really wanted to stick with my original. Lastly the tach I got is a lovely piece from speedhut which I custom ordered to match the coloring and font of my custom CRX Si cluster.

 

The white with a red stripe or the blue with a white stripe.
First gets hot when you turn the key to position I and other at position II

Cutting into the ignition switch wires is not the brightest of ideas.

 

Alright thank you. Since we're here though lets make this thread worthwhile for everyone else and discuss some of the reasons why it's not a good idea to do this? I'm open minded to opinions.

 

They are heavy gauge wires that are not easy to solder to.
You have to break through the insulation to solder to them. This exposes the wire to elements. These wires provide the power for all your cars basic functions. If one of them goes bad, it takes out a large portion of the electrical system.
There are easier ways to accomplish the same thing (like fuse box).
You don't have to take apart your steering column if you use a different way.

 

Good points. Im going to try what you had suggested earlier about the fuse box. Thanks for the info.