Solenoids:
These parts are mounted on the passenger side inner fenderwell and are responsible for directing power to the starter/gen. One solenoid is used for forward operation. The other is used for reverse. If you are having trouble with one direction but not the other, look to these solenoid or the related wiring. If you do not have a service manual, this would be one area that you should consider getting one to help you. The wiring diagrams will help you figure out where things go and what does what.
Some related links:
http://www.buggiesgonewild.com/gas-y...id-please.html
http://www.buggiesgonewild.com/gas-y...-diagrams.html
Alot of the problems I've read about have been attributed to loose connections, corrosion on terminals and connections, and frayed or chaffed wires. Make sure you get a really good flashlight and trace the wires you think are suspect and inspect them from one end to the other. Most times you'll find the issue.