All my electrical woes.

I have posted on here a bunch of times this past winter on various issues and have gotten a lot of good advice. Giving it one last shot on three issues, but I think I may be over my head. The car is a 70 Duster, 340 with a rallye dash which I purchased last fall. Been doing various things on it throughout the winter hoping to get a good riding season out of it this year. I do have a service manual and have downloaded schematics from this web site but I'm not an electrical guy so need help.

First is my radio, which I posted before about. Insert the key into the ignition switch and it powers up. This really doesn't bother me other than it's wrong. Car did not have a radio in it when I got it, got one refurbished and installed new speakers and the radio. The plug the radio plugs into has a yellow wire, a black wire and two red wires. Wiring diagrams I have do not show radio wiring at all.

This past week I had a fusable link on the engine bulkhead connector smoking. I traced it to a wire from the fuse box to the tach which had gotten pinched when I was reinstalling the steering column. I hope. I fixed that, but now my instrument cluster (oil press/gas gauge/water temp) does not work. Ampmeter still works. I see on other posts to look for a voltage limiter, could that be it/what does it look like and where would it be? Can it be tested or is it a cheap and easy to find replacement?

Third and lastly, my heater fan quit. Worked two weeks ago. Don't know what I did to that. Is there a way to test it before I pull it out? Have no idea how to get it out so that would be another learning experience.

I am sure I will get the rewire the whole thing answers but that would be a winters job for me (if I even want to attempt it) and I really want to drive this thing this summer. Driving seasons are short in central Wisconsin. I am not very competent with a volt meter, so it may come down to me finding someone around here that knows mopars, or else paying for someone else's learning curve while troubleshooting. Not a desirable thought! Thanks for any advice.