I'm not quite sure what you mean by "Main electrical system"? Thier is a fuse linking to certain features and to other fuses specificaly for when the key is turned. You'll find this fuse in the main panel under the hood, and a separate but equal fuse in the panel in the cab of the pickup, It will be labled as IGN for ignition. As far as the "Main electrical system", No, for the battery, the computer, and most other "MAIN" items, these items do not care if the key is turnned or not. If this doesn't answer your question. Please re ask your question being more specific about what you mean by "Main Electrical System" and even go further by telling me what your actually having trouble with that would lead you to believe that you needed to know about a fuse and tell me what your ending goal is. What's broke. I can fix that easier than fixing a problem that you don't know why it needs fixing. Happy Hunting.
under hood fuse box.
left side of steering or brake pedal
The circuit breaker for the headlights is intergrated with the headlight switch.
Same as any fuse in an electrical system- to protect components in the electrical system from damage in an overload or short circuit.
There is no fuse for the exhaust system, it is not electrical.
A fuse interrupts excessive current so that further damage by overheating or fire is prevented in an electrical overload or surge.
side panel on driver's right by the hinge on open door.
Left side and below the steering column. The cover has a finger pull, just pull out and down a little.
If all have failed possible fuse or brake light switch If only one has failed bulb or wiring to that fixture only
Its service Fuse Unit
The device that protects the home from the start of an electrical fire is an electrical breaker or in some older homes a fuse system.
Bad fan motor - Check to see if it is getting power Blown fuse Temperature sensor?