Question

wiring diagrams are usually found where?
lubrication guides
factory service manuals
unit repair manuals
owners manuals

Explanation:

Wiring diagrams detail electrical connections. Factory service manuals are comprehensive documents for servicing and repair, often containing wiring diagrams. Lubrication guides focus on lubrication, unit - repair manuals may be more specific to a single unit, and owners manuals are for general use and not as technical as factory service manuals in terms of wiring diagrams.

Answer:

B. Factory service manuals