OK, I found an article from a couple of years ago from someone out in Western Canada.
Here is what he said,
Thats kinda wierd because you rav shoulda bin equiped with 1. The cord should be located in the lower portion of the bumper/grill on the drivers side. I had a bit of troulbes finding the cord too as from the factory it is coiled up and barried with in the bumber. You mite need a flashlight and a pair of plier to fish it out. Good luck
After a lot af searching and inquiries for the part number for a block heater for the Rav4, I received this response from Metro Toyota. I ordered one for my 2005 Tacoma 4.0 L and one for wife's 2007 Rav 3.5L.
The Rav and the Tacoma will take the same heater. The
part number I use is 00113-00213-00900 which replaced the 885 number and the
889 number. It is the same heater for the prius as well. I currently have
these in stock but they move very quickly. They go for $49 plus shipping.
If you are interested you can purchase from my website listed below. Just
order one from the prius section. The model year does not matter. Again
they move extremely quickly and I probably will not have more until January