Can anyone tell me what the round connector at the end of the fuel injection harness is. It is similar to the water temp sender connector. At the end of the harness after the last injector connector, there are three connectors...A spade connector, the connector for the water temp sender, and the mystery connector! Thanks!

 

I forgot to say that mine is a 1990 4runner, 3vz six,auto,4wd

 

Put some pics up. it'll help someone know for sure what you are talking about.