RPM output connector

[Larry]

I was looking to use the green output connector that is located just forward ot the drivers side valve cover to turn on a dash lite at a designated RPM. I called Summit and they suggested I buy the MSD RPM Activated switch and the MSD Module that has a dial ranging from 6,000 to 8,500. For Ex. set the dial at 6,000 and any lite I have mounted in the dash will come on at that RPM. I ran the wire with the Green connector to the RPM inlet of the Activatd switch. However - at 6,000 the lite does not come on. I called MSD and they told me It depended on what kind of signal comes out of the wire with green connector. He said , if its a Minimum 12 volt Square Wave 20 degree duty cycle or a volt spike negative pulses 1 per revolution - that it should work. I am not an electrical guy- sounded all greek to me.
Can anyone tell me what type of signal comes out of that connector?
If not- is there a different wire I can get a RPM signal out of to run to this MSD module. I am running a fast sys - possible that illiminated any signal coming out of the green connector?? Larry

 

[Fuelie600]

I have a MSD rpm activated switch. The signal coming from the green wire you mention was not strong enough on my car. I had MSD mod the rpm switch for 2 cylinder use, and tapped a blue wire from under the coil pack. HTH, Brian

 

[TurboTR]

Larry if I recall you may need to pull that signal up to 12v through like a 4.7K Ohm resistor. There is probably info on that on the gnttype.org site.

TurboTR

 

[Larry]

Thanks guys - I will look into both suggestions here. Larry

 

[Larry]

Could use more help here. I did contact Caspers and spoke to John. He sent me a device that increases the signal from the RPM test connector to the MSD unit. I get it in there and still no light. I checked and rechecked the wiring - it all appears to be correct. I bypass the MSD and ground the yellow wire from the MSD ( that ran to the lite ) and the light does come on. I took the car out - set the module at 6,000 - I ran it to 6800 rpm- no lite! I understand I could send the unit back to MSD to be modified as outlined by Brian above- but, to save some time on our short season here in WNY- I'm hoping I can get this thing to work.
Could it be I am not getting any signal out of the RPM test connector? How could I confirm that. I have the Fast sys in the car - would that shut off any signal out of that connector?
Is there another line I can tap into to get an RPM signal? Thanks Larry