80 Door Lock Voltage Difference

Checked the voltage at the driver side actuator connector and found 12.4 volts. Passenger has only 9.2 volts...well, that answers the question of why the passenger will not lock/unlock...
Have spent the past few hours tracing wires and looking for bad connections but am not making any progress. Any ideas???

Here's a little more detail of the lock system status...
- door lock switches are less than 2 years old
- passenger switch harness is less than 2 years old
- actuators are new (just installed last week)
- just finished replacing the main lock mechanisms and cleaning/lubing all lock pivot points.
- lock mechanism works easily with no excessive pressure when I use the key and what pressure that exists feels the same on the drivers side where the actuator works well.
- am making an assumption that I don't have a bad passenger actuator given the lower voltage and that getting this up to 12+ volts will give the actuator more pushing power.
Last night, I cleaned the passenger actuator connector (sanded contacts and used electrical connection cleaner from Lowes). Plan to clean the drivers side tonight but do not think it will improve the situation given the drivers side works very well and the connection between the drivers side and passenger side is via a crimp connection at the drivers side actuator plug.
Only other two connections in the system appear to be under the dash in the right and left corners where the door harnesses (power windows and locks) plug into the dash harness. Sound about right?





