main relay
James,
You may have disconnected the interlock control unit instead (if so, you will know if you can't shift out of park with an A/T without it connected and with the engine running). On my '90, the two relays are located 90 degrees to one another.
Look at the color of the wires in the harness to tell if you got the right one. It may be different on your '88, but the wiring on mine is yel/blk, blk/yel x 2, blk/wht, grn/blk, and blk. Check your manual to be certain of the wire colors.
good luck