Micro Aftermarket keyless entry intermittent on 1994 Toyota Camry

[spokanekevin]

I have a 1994 Toyota Camry XLE with power door locks and no factory keyless or alarm system. We added a Micro DLR4V keyless entry system. Remote locking works 100% of the time. The receiver is tied into the following wires in the car: lock, unlock, two grounds, constant power, ignition, and park lights. Remote unlock sometimes works and sometimes does not. When remote unlocking does not work, the following are all true:
- The system receives the signal and flahses the park lights as expected.
- The LED indicator on the Micro keyless entry system goes out as expected.
- The doors do not unlock. Repeatedly using the remote repeats the light flash, but the doors still do not unlock.
- After unlocking either driver or passenger door with key, the unlock function works again from the remote. You don't have to open the door, just unlock either one with a key, and then you can lock/unlock as much as you want with the remote FOB.
- The behavior is intermittent. Sometimes after a short stop the system works, other times is fails to unlock as described above. Sometimes after sitting all night it's fine, other times it has the problem.
- The most interesting thing to me is that 100% of the time I can simply turn the key in the door and do nothing else, and it's back to working (but that takes away from the point of having keyless entry). This suggests to me it is not a short or break in the wiring, but possibly related to the door lock cylinders, but not sure how so.

I believe the keyless entry system is functioning properly, but something is preventing the door unlock signal emitted from the Micro receiver from reaching the door locks. I have read that there is another component in the factory power door lock system known as a door lock position sensor, but I am not sure if these parts are causing the problem or if there is a way to test for that.

My mechanic doesn't get involved with aftermarket electrical items like this. The places that sell the systems don't want to work on it either, they just want to sell a new keyless entry/alarm system. But if the system is working and the problem is elsewhere between the system and the door locks, and a new system would be tapped into the same wires in the harness, I don't think a new system will solve the problem.