I just replace my harlan with a summit rpm switch. The instructions they gave me was a little confusing, I hooked up the red(+12v), Black ground, and White (tach signlal) correspondingly, However there are two remaing wires to connect, on the instructions they sent it said:
"Gray wire normally provides a ground for a circuit and will open upon reaching the selected RPM limit." and
"Yellow wire is normally open and provides a ground for a circuit upon raching the selected RPM limit."
Correct if I am wrong, but doesnt those two sentences sound the same? Aren't they doing the same thing? So the question is , would I connect the +12v wire of the solenoid to power and connect the ground (solenoid) to one of those wires and at the specific RPM, it would open and provide a ground for the solenoid?
Also would I also need to put a relay in? Thanx

 

After rereading the instructions, I realized that there is a differnce between the two wires- Gray: provides the ground but when rpm is reached, it goes open. Yellow, is open and when rpm is reached it provides the ground. Now with that figured out, which wire am I suppose to connect? I tried to connect the ground of the solenoid to the yellow wire and the power (solenoid) to the battery and set the rpm to 5200. There was still no activation nor did the green led turn on when it hit 5200 rpm. Could the switch be defective?
Even if I were to not connect any wires, if I was to set the switch to a certain rpm, when that rpm is reached, should the green led come on anyways? I recheck rpm tach signal and I am positive its getting a signal to the switch so what gives?

 

I took it off the coil pack #6? (lower front) same as the harlan. Okay, i will try that tomorrow. Is there a reason why, wouldn't the tach signal not be as accurate as the one off the coil pack? My tach a little compared to the actual signal to the ecu (shown on my SAFC).

 

The best thing to do is use the TAM screw on the back of your Speedo console in the dashboard.
The grey wire isn't used. The white goes to the solenoid and the yellow goes to the TAM screw IIRC.

 

Thank you, I apprieciate the help. I will change my tach signal asap. Do I need a relay or would it work fine without one?