shorted out 12 volt system

The only way to fix a short circuit is to lengthen it. On the serious side, the entire thread is somewhat confused, vacillating between a “short” circuit and an “open” circuit. As stated by RJSfishin, there’s a big difference between the two. Based on your description of what happened, it looks like you have an “open” circuit, either due to a blown fuse, or a burned wire, caused by the high current short between the terminals, although a short across the battery usually will not blow a fuse, unless connected to shore power, in which case the fuse between the battery and 12 volt load will blow. A short across battery terminals can easily weld something, like the wrench, and is a dangerous act. A good practice when connecting a battery is to connect the ground terminal of the battery last so a wrench short to the chassis won’t make sparks and smoke.