Originally Posted by austinramsay
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
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.