My what is it, do I need it, what's supposed to go there, how do I fix it post.

[gordyzx9r]

So, I'm trying to take care of a few minor things with my new old 1970 C10 I picked up recently.

I'm finding a few odd things here and there that I'm not sure either:

What is it?
What's it do?
Do I need it?
What was supposed to go in that mounting bracket (that nothing is mounted to anymore)?

I'd really like to gut anything and everything I can related to emissions controls. I don't live in an area where I need it...and most of it is dry rotted, capped off, and lines just sitting there anyways not connected to anything.

Is there a really good fuse box diagram somewhere? I downloaded the Chevrolet Chassis Manual from this site, but that's not exactly crystal clear.

The fuel gauge is not working. I need to troubleshoot that. What resources are there here to do that? There is a wire running from the center of the top of the tank (which I assume is the sending unit) directly to the fuse box. Is it supposed to be? Just to see what would happen, I pulled the plug out of the fuse box and the gauge went past full. I put it back in, and the gauge goes to empty.