I removed the whole unit and disassembled it. The box contains no cogs other that the one on the servo motor shaft! must have had a big - time failure at some time. Checked the servo motor with a stand alone battery and worked fine, both directions. Would appreciate some voltage specs and testing procedure for the plug from the PGM that connects to the servo. I was hesitant to poke around with the multi-meter and fry the PGM or TPS.
If this checks out I'll buy a complete unit and all should be fine.
Cheers Dave.