Topic: Need to know what plugs into transmission on 1989 trans am

[1989GTA]

I am working on installing the trans in my 1989 Trans Am GTA today, but there are three connections to the transmission.  I have a 700r4 going back in, and it only has two plugs on it.  My book says the connections in the wiring are : Lockup, 4th gear, and coverter.  One is big with 4 plugs, one is very small and oblong with two wires, and the other has two long plugs.  The trans is from a 1992 4x2 truck, but it matches exactly with the 89 truck trans I have.  I know where the big 4 wire plug goes and have found where the long two plug goes(looks like it goes where the speedo should be).  What is the 3rd one for?  I see that supposedly one could get the 200-4r trans as an option, could this be a connection for that?

[mastiso77]

Every 700r I delt with (the ones with the detent cable) all have 2 plug ins. The big one for the lock up converter the the little one for the electriic speedo. You stated that when you bought the car you also got the computer and wire harness. Is it the one that was on the car before the guy stripped the drivetrain? Maybe the 3rd wire goes somewhere in the engine compartment.