What is the little..., PLEASE HELP ME! Options

[Chrobis]

Ok, as I mentioned in another topic I am having problems with my swap. Well everytime it fuel cuts I hear a relay click in the dashboard, right where the ECU is mounted. Well, I pulled back the carpet and got a good look at the thing, and its a little black box next to the ECU. It is a 6 pin connection, only 5 pins being there, the wire colors are as follows:

BLK BLK/RED BLU/BLK
WHT/BLK BLANK GRN/RED

My mechanic said this was not with the engine pack, and since used the one from the original car (97 GT). Mike (qatar) did the harness, not like that changes anything. So my question is, what is this thing? what does it do? And do I need one from a 3s-gte car or would the 5S-FE one work?

And no the car dosnt run with it unplugged, it turns on, but then stalls.

I know this is probably not the right forum for this post, but I need as many people to see it as possible.