sprint, I found the thread you commented in.
http://67-72chevytrucks.com/vboard/s...d.php?t=776599
So basically, using this transducer eliminates the need for the diodes and resistors and tapping into the low and high speed trigger wires at your fan fuse block and instead uses the readings from the pressure line to provide feedback to the PCM which in turns does whatever you tell it to do, via those low and high speed trigger wires. Right?