Pontiac: torque converter clutch system, torque converter clutch, 1984 pontiac fiero

Question
I have a 1984 Pontiac Fiero.  When I drive it down the road (aprox. for 5 minutes or so) the "service engine soon" light comes on.  I did a diagnostic test on the computer.  It revealed that the light was coming on because of the vehicle speed sensor.  The manual I have indicated that there was a sensor on the transmission somewhere around the distributer.  I couldn't find it.  So I went to a parts store and asked for a speed sensor for that particular car.  The one they sold me didn't match anything on the car.  I then read another manual that said that the vss was located in the instrument panal.  This particular car may have had the transmission changed.  I'm not sure of this.  There is a speedometer sensor that is hooked to the speedometer.  The speedometer works fine.  I traced all the wiring to the speedometer and the brown wire to the ecm from the speedometer.  I also checked the connections at the ecm.  The purple and yellow wire from the sensor to the speedometer are connected solid.  There is a hot (yellow wire) that is fine too.  I also checked the ground wire.  It's fine.  I even checked the ecm to be sure it was grounded.  On the diagnosic plug, I found that the "f" terminal is the circut for the converter clutch.  I grounded the "f" terminal to the "a" terminal to see if the clutch would funtion.  It worked perfectly.  When it down-shifted or when you hit the brakes, the clutch would release.  On this year of car, is the vss located in the speedometer or on the transmission?  Are the speedometer sensor and the speed sensor the same thing?  Could you please give me any input as to where to go from here?  By the way, in my manual it indicated that the neutral/stop switch or the tps setting could be at fault.  I checked the neutral/stop switch and it seemed to function ok.  I also checked the throttle position switch voltage, and it seemed fine according to my manual.
Thank you very much  

Answer
Your VSS could be located at either place depending on which engine and trans set up you have. If you have acable driven speedo, the VSS shold be on the speedo head. If you have an electric speedo then it is usually in the trans.
Since you said the speedo works fine I am assuming that the VSS is on the speedo head. Not sure why you are checking the conv. clutch though.
Now just because the speedo and VSS wires have good connections does not mean that the VSS is putting out the correct voltage to the ECM.