I have a door lock actuator issue that I don't think is specific to my 1994 C4 Corvette, but likely applicable to other models.

The power door locks work on both the driver and passenger side doors when using either door lock switch. However, the key fob only unlocks the passenger side when the doors are manually locked. If the doors are unlocked, the key fob will not lock the doors. The key fob unlocks the hatch fine. I thought this was a lock actuator problem so I replaced the actuator with the same results.

When the doors are manually locked or unlocked and the switch is held in place, I read about 10.8 volts on my multimeter. If I just lock and unlock the doors without holding the switch in position, I only read about 0.7 volts, but I think that is because the action is so fast, my multimeter does not register the actual voltage fast enough and that is whey I need to press and hold the switch to get to 10.8 volts. If the doors are locked, and I press and hold the key fob button, the volt meter only shows about 0.7 volts again, but since I don't think pressing and holding the key fob is the same as pressing and holding the door switch, so I am not certain what is really being sent to the actuator when the key fob is pressed as don't think the multimeter is fast enough to read the correct voltage.

If the doors are locked and I press the key fob, the passenger side again unlocks and the driver side does not unlock, but if I am holding the actuator in my hand, I can feel a very slight vibration like the actuator is trying to activate. Again, as discussed above, not sure how to confirm if the right voltage is being sent when the key fob is pressed - possible that the correct voltage is not being sent when the key fob is pressed that is why a slight vibration is felt when the key fob is sent.

Any thoughts on how to further trouble shoot? I think the key fob is good and I think the lock actuator is good.

Update: I have since tried to reprogram my key fob and the system appears to allow me to re-program the key fob as per the manual; I get the PassKey flashing light when I am in the programming mode so at least I know the PassKey light is functional and appears to be working normal. However, part of the instructions in the manaul also diccuss that you can turn on or off the PassKey feature, and you can tell if it is on or off if the PassKey light shows up on the instruement panel. In turning the system on or off, the PassKey light never appears. Therefore, I am not sure if this is an indication that the PassKey module may be what is actually bad and that may be what is causing my door lock/key fob to behave as outlined above.

Anyone experience something similar to know if I should be looking at replacing the key fob or PassKey module. If I read correctly on other forums, the PassKey module is not trivial to get at without taking about the whole dash.