Keyless Entry Randomly Activates

I need your help. I'm about ready to tear my hair out. I installed a keyless entry system on my 1996 Toyota Previa DL S/C. Everything works like it should (simple lock/unlock with parking light flash), except for one irritating thing... It locks/unlocks itself at random times, no matter what the Bean is doing. Sitting, driving, parked, whatever. As I'm driving down the street, sometimes it will get on a roll and lock/unlock itself 4-5 times in a row. Then, it won't do it again until I push the button on the remote. Or, like tonight, I was working on seeing if I had a short somewhere, and it was locking/unlocking itself randomly.

I can't figure out what would make it activate randomly like that. Does anyone here have any ideas?

Also, what are the four wires for in the black cigarette-size box that is at the end of the steering column just as it goes through the floor board? It has a white sensitivity adjustment knob. I'm
assuming this has something to do with the seatbelt light and sensing weight on the driver's seat. There is a green, black, yellow, and red wire. Right now, the green is connected to
something going into the upper floor board, right above the false pedal. The rest are not connected to anything.

I've cut out the old alarm system. I don't think it was factory, as it had zip ties and wire clips connecting some of the wires. Although it was very neatly done and seemed to be loaded with
features (ignition cutoff, horn alarm, battery sensor, door lock/unlock, etc.), I am unable to figure out what kind/brand it is.

Someone just suggested that perhaps the unit's antenna might be over-sensitive and picking up signals from the remote (which is usually hanging from the keychain in the ignition). Should I cut the antenna off the unit?

I'm open to all suggestions and ideas!
Kathleen

Are there any wires still installed from the old alarm? If so something could be activating the door locks, or getting a voltage spike from your new alarm.

Chris,

I've cut out the old wiring harness. What kind of wires would produce a voltage spike? I mean, what kind of old connections would I look for? I can't say that I disconnected all the old connections because I'm not sure that I did. All I know is that I've pulled out the old harness. Do I need to tape all the wire ends even though they're cut?

Kathleen