help! .....wiper problem!........ help!

[yote1234]

im going crazy trying to figure out the problem..im finishing a complete body off restoration of my 72 cheyenne hugger 1/2 ton truck.installed nos wire harness,all brand new gm stuff. ...... so i installed the new wiper motor and it doesnt work.? i re installed the old one and it doesnt work. i removed the old one and tried to bench test it. when i turn the shaft then touch the wires to it (hot/ground) it starts up and runs the shaft 1/2 turn,i turn the shaft back 1/2 turn and touch the wires to it again it will turn 1/2 turn again. so i figured out the 1/2 turn is only a "return", but i cant get it to make a complete round. it is a 2 termanal plus ground. i have nos wire/fuse/switch/motor.
im still in dash assembly stage. ............. any ideas?