97 psd ,trying to understand this circuit as it seems the way the tach operates is the more v,increases the reading of needle during operation.Was testing the cluster backside for wire contunity and found only 2.7v with 12 v supplying power.What has me concerned is that this is pin wire 50 white/pink and is pin 50 from the pcm.In essence the pcm sends current it receives from cps for tach?Thanks again,Ron

 

Looking at the Service manual...12v goes to tach and the ground is varied on what the PCM "sees". Is your tach inop or erratic?