Hello, I realize this is an old post but I found out a way to get 400 watts out of the factory inverter while in drive. There is a green wire on the back side of the inverter switch on the dash that looses it's ground when the van is taken out of park. All you have to do is cut the wire and run the leg from the switch directly to ground and you have 400 watts available any time you originally had 150 watts available. The only downside I have experienced (albeit very minor) is that the 400W on the rocker switch stays lit up anytime the ignition is ON or ACC. The outlets however are not powered until you push the switch and both 150W and 400W are lit up. You could block the light from the led from lighting the 400W portion of the switch if it bothered you. It doesn't bother me. We now have power to run our crock pot while road tripping.
