No, the solder doesn't melt. It's used in the socket connectors to provide a better electrical connection (fills the gap) ...much easier to get it working this way than to dismantle/replace the fuse box.
Thumping on the fuel tank to get the pump started? You might try dropping the spare tire for better access to the fuel pump connections. Then pull the connectors and spray some contact cleaner on the tank pins and plug sockets. Factory fuel tank connectors a notorious for faulty conductivity over time and are replaced via splicing during pump replacement.
Good luck!

 

It's fixed....new fuel pump was installed. Although I most likely could have done it myself I had the garage do it for $580. I'm getting a little on the old side (60's) for crawling on my back. I will, however, tackle the next little job...front wheel hub. It pretty much looks the same as what was on my 1993 caddy front wheel drive.