The vehicle is a 1990 Dodge D150 Extended Cab. The battery is charged and connected; however, electrical power does not seem to get to anything. No interior/exterior lights, no gauges, no starting, not even the buzzer that indicates the key was left in the ignition when you exit the vehicle. Occasionally, the power gets to everything and the truck starts, runs and everything works fine. Is there a relay that has to operate before power gets anywhere, or do I probably have a loose connection on the ground or 12V line?

. Begin by testing all under-hood, under-dash fuses, and mega fuse with a test light or multimeter. Here's how:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post252145

. Remove battery and place on a charger, clean battery terminals, and clean cable connections.

. Check/clean main engine ground.

. Check ignition switch and harness.