Thanks for that reply. That makes sense to me now. That solid state unit is likely a signal buffer to clean out the spikes from the vehicle speed sensor signal to the speedometer, and the later model cars may be using the buffer circuitry that's already in the PCM for the speed input data or possibly the cruise control module if later ones still even have those? The factories seem to always move more and more of all the electronics into the PCM as cars get newer since so many other systems on the car will share that data, it makes sense for them to spend less, and have the PCM do all. No need to have more than one buffer on the car for cruise control, speedo, and PCM speed signal. That makes sense. So I just ordered me the earlier of the 2 units for my swap (pre 1/98), because I need the type with self contained buffer unit since I'm doing a cable to electronic speedo conversion to my car. I have to do this to get the new indiglo gauges of mine to fit my car.
