FYI...
There are MANY instrument-systems and electrical-systems and avionics-systems and avionics/instrument [black-box] training manuals for technicians-in-training... and engineers-in-training. WAY too many to mention here... and many disciplines interact. My head hurts.
Start here...
Here is a tiny-tiny-tiny slice from my master list of stuff...
AIRCRAFT DIGITAL ELECTRONIC AND COMPUTER SYSTEMS, ISBN 978-1032104805
AIRCRAFT DISPLAY SYSTEMS, ISBN 978-1-56347-657-0
AIRCRAFT ELECTRICAL AND ELECTRONIC SYSTEMS – PRINCIPLES, MAINTENANCE AND OPERATION, ISBN 0750686952
AIRCRAFT ELECTRICAL SYSTEMS, ISBN 582988195
AIRCRAFT ELECTRICITY AND ELECTRONICS 7TH ED, ISBN 9781260108217
AIRCRAFT RADIO SYSTEMS, ISBN 9780891003564 [1990]
AIRCRAFT SYSTEMS: INSTRUMENTS, COMMUNICATIONS, NAVIGATION, AND CONTROL - AVIONICS TRAINING, ISBN 978-1-119-25954-1|
AIRCRAFT SYSTEMS: MECHANICAL, ELECTRICAL, AND AVIONICS SUBSYSTEMS INTEGRATION, 3ED ISBN 978-0-470-05996-8
AIRCRAFT STRUCTURES AND SYSTEMS FOR AVIONICS MAINTENANCE, ISBN 9781941144183
AIRCRAFT WIRING AND ELECTRICAL BONDING, ISBN 9780983865803
AIRCRAFT WIRING AND ELECTRICAL INSTALLATION, ISBN 9781933189079
AIRCRAFT WIRING GUIDE - THE PRACTICAL GUIDE TO PLANNING, WIRING, AND ENJOYING THE ELECTRICAL SYSTEM IN YOUR EXPERIMENTAL AIRCRAFT
FAA-H-8083-6 ADVANCED AVIONICS HANDBOOK
FAA-H-8083-30 AVIATION MAINTENANCE TECHNICIAN HANDBOOK - GENERAL
MIL-HDBK-535 GUIDELINES FOR TROUBLESHOOTING OF AIRCRAFT ELECTRICAL WIRING AND INTERCONNECT SYSTEMS (EWIS)
Ta-da...