I have a T5 from a '91 s10 with electric speedo drive, so today I went to the local Pick&pull and got an electric speedo from a '93 s10. My question is how do I hook the electric speedo up, in the pic there are 8 prongs on the back of the speedo. 4 are for the speedo and 4 are for the odometer. I am assuming the 4 wires are power, ground, 1 wire going to the trans sensor and 1 wire coming back from the trans sensor. If that is how it is, how do I identify what wire is what? or if that isn't the way it is how do I find out what is what?
back of speedo


1938 Gmc 1/2 ton