I'm trying to install a factory cruise control kit on my 98 Brighton wagon. Everything is in except the ECU. There's no plug where the instructions say. Can anyone tell me where their factory cruise ECU is mounted?

It's there, look harder.

Do a search. There are couple of treads concerning CC install.

If 10? prong black connector is not behind glove compartment (that's where it was supposed to be according to installation instructions), then it is under the dash. In my case (96' brighton) finding mounting place under dash was obvious - there were two bolts sticking out of the metal plate.