For easy wire changes (plug-n-play), here are some adapters on eBay.......it's what I used when I made the conversion to H4 bulbs.

http://www.ebay.com/itm/WIRE-HALOGEN...5VfT-8&vxp=mtr

Here's a link to a write-up that might have some helpful information.
http://www.toyotavantech.com/forum/e...nd-Previa-dude