None of the electrical components were were working on my tailgate, so I pulled the drivers side rubber boot and found 9 of the 13 wires were broken. Nice. Patched in 13 new one foot sections of wire and have got everything back working except the power tailgate lock. Have verified the actuator is functioning with battery voltage. When I check the two wire plug going to the actuator I get about 8.5 volts (voltmeter) door open and door locked. With a test light to ground on each wire I get no light door open or door lock. What is my next step to troubleshoot this system or maybe there is something easy or stupid I am not doing.
Any help would be appreciated.

 

Were you getting 8 volts across the terminals (positive to negative) or from the positive terminal to a chassis ground? Where you took your readings makes a difference.
The release is a solenoid and 8 volts isn't enough power to actuate it.
It could be something as simple as a bad ground.
It could be the actuator needs to be cleaned and lubed.
It could be the coil in it is cooked.

 

8 volts across the terminals and from the positive terminal to ground both are 8 volts, understand 8 volts is not enough to actuate the solenoid. Actuator is not the problem, I have a new one. Tailgate seems grounded, wiper motor has 12 volts. My son thinks its a bad relay in the door lock control. I think that is in the drivers door? Anybody know for sure where that is?

 

I had the same problem, everything worked after I soldered up the 8 broken wires, good luck!

 

It's on the same side of the car as the steering wheel, up towards the front.
Just behind that big sheet of glass at the back of the hood.

 

Got it working. It was the ground wire in the five wire power door lock harness. Of course after I got power to the actuator plug and plugged the actuator in it still didn't work. The plug was corroded and not making a connection. Cleaned and greased it and all is good.