Step one of this problem broken down into parts:
1) Chart each electrical box showing each cable entering that box AND the wire colors. That is all you do the first time.2) Show each dedicated connection either via wire nuts or using the receptacle.
3) Take the meter. Measure and record each voltage on each red and black wire (relative to the white wire) inside each box both with switch on and with switch off. For example, the label adjacent to a wire might read "123/0" for a wire with switch on and off. Or it might read "122/123" for that wire.4) Now we are ready to start learning what connects to what. Some connections will be obvious. Notice at no time did I every advocate disconnecting anything. Disconnecting to learn only comes after we have definitely established what boxes interconnect with which cables. The unknowns on that map are learned by selective wire disconnects only after questions remain.
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