melting fusable links

on my 96 dodge 3500 van when i turn on the ignition it melts the fusable link and i have found that one end is hot all the time and the other end is grounded only when the ignition is turned on, but i can not figure out why it is grounded.

I now have found that if both of those relays under the master cylinder are plugged in, it will melt the fusable link, but if I remove one of them it won't melt it. I believe these two are the fuel pump relay and the automatic shut down relay, buit witch is witch?