proctors garage

Looking for some much needed help. I have a 1996 dodge 3500 diesel i'm working on that is locking and unlocking the trans converter. I have adjusted tps,changed brake light switch, cleaned all battery connections and grounds at fenders added ground to computer case , unhooked alternator.This morning I unhooked alt. and drove it at first I thought that was it then it started back so I thought it might be temperature related. Then with scanner I noticed trans temp was -83 voltage was about 2.8 so I unpluged trans valve body plug voltage went to 4.8 but temp stayed at -83. Some people say seperate wires and wrap in foil. I'm stuck run out of ideas any help would be great.