So, avoid MS3 stuff if you have an MS2, it might just get you on the wrong path.

You should find out who made your MS2, but if you got it used, you may not be able to. It is probably something similar to the ones Symtechlabs makes, but either way, they have a good diagram here:

http:// www. symtechlabs.com/support/docs/MS_Wiring_Guide_420A.png

The pins that should interest you are the idle one (FIDLE) in yellow, and the "SPR" ones.

Others may be of use as well. You can track your jumper leads down to where they are attached to the board. Each will have the name of the MS pin that it goes to by where it is soldered in. If you use that on your harness, skip it and find another. If you don't use it, then see if it is available as a tacho output pin on the table.

FIDLE can drive a relay of a certain size (kinda small). The ohm load needs to be about 50 ohms, from memory, but go find that in the MS hardware manual (I don't have time to find it right now). If you try to run a relay that is too large, you'll over current the transistor that is in there by default.

For the tach, you'll need to build a small tacho output circuit. you can find these online for your application. (420a?)

You can run them out one of your unused SPR outputs, if any are available.

If it helps, I have some videos on youtube that go over the build process of a MS2 board.

That starts with EP 2 here: