Okay, here's the deal. I have a 1991 RS, which I placed a TH350 transmission
into. The RS uses a electronic sending unit and the TH350 uses a cable unit.
I purchased a adapter from VDO to plug into the transmission.
The VDO sender has three wires a red, black and clear. The RS has two
wires for the sending unit yellow and purple. My guess is to wire the black to
the purple for ground, and the yellow and red for hot. Then wire the clear to
the ECM. However, I don't know which wire to connect it to in the ECM.
Is this way off base?

 

Here is the sending unit I purchased from VDO.