So I have a 2007 VLX, and want to take it out but cannot find the hole for the last plug, I found the one underneath the wedge(I believe its the transom plug) and put the one in the center of the floor, but where does the last one go?? I know its somewhere in the engine compartment i believe??? Any help is appreciated, Thanks Guys

take it out, and find how the water is getting in. Then you will have your answer.

look underneath the boat that will help

Does the boat have a glove box/cooler plug? Some do.

The third plug is underneath the vdrive/transmission area[i'm assuming you are talking about a Malibu VLX]. Take the center seat of the back row off. it is straight down and to the right of the v-drive.

got a water hose?

jeff is correct, but you could have always done as suggested and put a hose in the bilge and then look under the boat for your answer