If the voltage is negative, make sure you don't have the polarity reversed. As far as the power supply, it comes through both a fusible link and a circuit breaker. The wire is white but splices to red before going into the control. Also, the ground between the two seats is spliced and ground is located under the driver's seat, attached to the floor.
See the attached pics. It shows the wiring schematic for both front seats.
Let me know if this helps you.
Joe
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Tuesday, March 10th, 2020 AT 8:50 PM