Aftermarket Tach Install? Which wire to tap into?

Im installing an equus tach i got on craigslist that was still in the box brand new. I searched and found that you can use the black and yellow wire going into the ecu but id rather use a wire behind the cluster to connect it. Do i still use the black and yellow wire behind the cluster or is it going to be a different color?

Thanks!

 

Anyone?

 

For future reference when searching.. I just took the green wire from the tach and plugged it into each port in the instrument cluster harnesses until i found the one that put out the rpm. Its the plain black wire that goes to the blue colored connecter. I cut it, stripped it and connected all the tach wire, and both split ends into a wire nut thingy and twisted them all together. I also used the power from the clock harness which worked fine this was on a 1996 tacoma btw

 

Too late, i knew i was gonna forget to take pics while installing.. And i did. Its all back together already so i cant take any

 

Ohh haha ill post pics tmrw, its 12:30 already and im too lazy to go outside.. And ill get better daylight pics

 

I HIGHLY recommend not using wire nuts for any vehicle application. They are designed for home electrical because bumps and lots of movement make them fall off very easily, and the little spring inside comes out easy. You can fry your cluster and even your ecu if that happens. Highly recommend taking it apart again and if you can solder, do that and cover with electrical tape and then zip tie, if not then at least use a butt (barrel) connector.

Not trying to bash you, just trying to give you a heads up for next time so dont take this personal. Just trying to help. Oh and also, very very bad things can happen by testing wires the way you did. I would try to avoid that by any means necessary. I knew an installer who broke his neck (paralyzed him) because he accidentally set off an the airbags by poking random wires like that. Several people have done thousands of dollars in damage like that. Just letting you know to be careful or pay to have it done right.

EDIT: one last thing... an aftermarket tach gauge im sure uses very very low power to run, so using power from your clock wire "should" be ok, but you have to keep in mind that different size wires are rated for different amounts of current and amperage. By connecting an accessory to another small accessory like a clock may not supply enough current through the oem wire. This results in the wire getting hot and starting electrical fires. Hope you used a small 5 or 10amp fuse (or even 2.5 maybe) when tapping power from your clock.

 

Oh thanks! I didnt know you shouldnt use wire nuts in cars.. Guess im gonna have to take it apart again So how would you find the correct wire to use without plugging it into each port?

 

A wire schematic is ideal, but if not then you need a digital multi meter (dmm)

 

Wow! Putting a tach on top of my dash a good idea? 2.7 4x4 5 speed?