To find the relevant fuses and relays, you need to consult your owner's manual. It will have a fuse box diagram showing the locations and amperage ratings of all fuses and relays, including those related to the air injection system (often abbreviated as AIR or SAI). The specific fuse or relay may be labeled differently, such as "AIR PUMP" or something similar, but it won't be explicitly called "secondary air pump".
Look in these locations:
* Underhood Fuse Box: This is the most likely location. The owner's manual will show you exactly where this box is and how to access it.
* Passenger Compartment Fuse Box (Interior): Some vehicles have additional fuse boxes inside the cabin, but the underhood box is more common for high-power components like the secondary air pump.
Without your owner's manual, I cannot give you the exact fuse location. Searching online for a "2003 Cadillac DeVille fuse diagram" might yield a PDF you can download. However, always use your owner's manual as the primary source for this information.
