Crazy Electrics...
sounds like a bad t/s switch to me. the contacts get worn off and then you have to hold it L or R to get them to work. sometimes the pivot pin wears out the plastic and you get the same thing. also, if you are going to remove the cluster, disconnect the battery first. then when you pull the cluster back a little you can undo the ammeter wires as you lay it back. i've found it much easier to do if you lower the steering column. don't take it out, just drop the top bolts and lower the column a couple of inches.BTW the ammeter nuts are 3/8" and its double nutted. i hold the one under the wire and turn the one holding the wire so that i don't break the stud off of the wire inside the gauge. good luck man. this aint no big deal. just take your time,and if you get in a bind just post back here and we will help. i guarantee it.