Freightliner century electrical issue

What year?

 

Broken wires, blown fuses, bad relays, corrosion on the connections etc etc can all cause you to lose power to a hot wire. You need to know which wire is hot and start tracing it from the connector. Sometimes the spade connector itself may look good but it can be corroded enough to not carry the power.

 

Ck the fuse panels after you have been driving in the rain for a good amount, look for any dampness on` them, and fix the windshield leaks, then take a picture of fuse panels and pull all the fuse and breakers out and clean, all con. in fuse panels and prongs, if it's bad leaks running on the panels you want to put them inside a big heavy duty zip lock bag and use a tube of gasket maker to seal up the holes that you had to put in to run wires through, don't think that you fixed it by cleaning fuse boxes and finding it all works, because when you drive it in rain next time it will not turn off any time you turn key off?