I have those lights lying around too and was thinking along the same lines. Which SPV harness is it, and do the lights come on with reverse, or via an upfitter switch?
I have mine wired to do both, reverse and upfitter switch
SPV Harness:
SPV Parts FULL LENGTH REAR Harness - SPV Harness System (Works with MANY vehicles, See Details) - Standard (Includes Add on Connectors for lights without connectors) / No - No Relay Needed
SPV Parts Harness Taillight Connector Adapter (Powers Reverse Lights/Backlights) - SPV Harness System (Works with MANY vehicles, See Details) - 21-24 Ford F-150 (Raptor/Lariat/Limited/Plat/Tremor) (LED Tails)
SPV Parts Harness 2 Pole MOLEX Connector Adapters for Ford OEM Rigid Fogs (Pair) - SPV Harness System (Works with MANY vehicles, See Details)