Final answer:
The wire color designated for stop lights in a 7-way tractor trailer electrical cord is typically red.
Step-by-step explanation:
In the context of a 7-way tractor trailer electrical cord, the wire color designated for the stop lights is typically red. Each wire in the electrical cord has a specific color assigned to a different function. For example, other colors like brown may be used for tail lights or license plate lights, and blue might be for the brake controller output. The electrical cord allows the tractor and trailer to connect so that all necessary lights work in sync, which is crucial for the safety of the vehicle on the road.