There is nothing wrong with the test light. It will work perfect.
As far as the one actuator working in one direction could mean it isn't getting power from the switch in the directions that doesn't work or the actuator is bad. The only way to be sure is to take your test light, and see if power is sent to the actuator when the switch is in the opposite direction. Now how this works is simple but may be confusing. All that happens when you select to lock or unlock the door is the polarity (12v) to the actuator changes direction. There are two wires to the actuator. One is pink/orange and the other pink/black.
When you check for power, when the switch is in the unlock position, the pink/black wire should have power. When it is in the lock position, the pink/orange wire should have power. If you have power to those wires I mentioned under those conditions (switch position), then chances are the switch is bad. As far as the driver's door where nothing works, you still could have power and no ground. That is the one that doesn't work at all. On the passenger side, it does work one way, so ground is okay.
1) Starting with the passenger door (the one that works one direction), check for power as I mentioned above. Since the it will lock, the pink/orange wire should show power when pressing the switch to the lock position. Make sure there is power to the pink/black wire when you place the switch in the unlock position. If there is, replace the actuator. If there is no power to the pink/black, replace the switch.
2) The driver's door is a little different. Since it does nothing at all, we need to first check if power is available to the actuator the same way as passenger side. If there is power in both directions, then we need to confirm there is ground. If you have both power and ground, replace the actuator. If there is no power, we then have to go to the switch and confirm there is power to the black/white wire powering the switch. If there is not power, check where the break is. If there is power at the switch and not to the actuator, replace the switch.
I just reread what I wrote and it sounds confusing. Ugh! I'm trying. If step 2 above is confusing, just check (using the test light) if there is power to the actuator and let me know. If will further direct you at that point.
Please let me know if you understand what I wrote. Also, if you have questions, please let me know. In all honesty, it is a very simple circuit. I most likely am not making it sound that way.
Saturday, April 18th, 2020 AT 9:58 PM