Heater/ AC wiring
Here's photos of a non-A/C heater the sellers claims are from a '70
Green wire is power from the reisistors to the motor.
The brown wires are ground.
I can't be sure '70 is the same but one of the brown wires runs along the back and under the passenger side kick panel where it is screwed to the body with a ring terminal.
More likely, the combined A/C Heater unit was retained.
The power to the blower motor on those is routed to the engine compartment.