OK, I dug out my notes. Slight correction to what I said above.

You send either a positive pulse or a ground pulse out to the same YELLOW wire (on my car) at the trunk latch.

Ground locks the car.
Positive unlocks the car.

So hook your relay outputs this way.

It's a half hour job, I really recommend it.

__________________
Cheers!
Scott McPhee

1987 300D