Lexus RX-330 Trailer Wiring - HELP! KWW

[PhxWilsons]

I have a Lexus RX-330 that does NOT have the factory towing package. I've installed a receiver hitch. I purchased the trailer pigtail from the Lexus dealer for $63 - ouch. After finding the correct male hook-up for the pigtail, I find there is no power in the receptacle coming from the vehicle's wiring harness. Any ideas on why I just can't plug in the 4 flat pigtail and go?

[PhxWilsons]

It turns out that some (not all ) RX-330s ordered without the towing package do not have a junction block (part 82670-0E040 $225.16 + $200 for installation) installed. Without the junction block, there is no power supplied to the trailer wiring receptacle in the rear of the car. The dealer cautioned that if a non-Lexus trailer light hook-up was installed and there were ever ANY electrical/computer malfunctions, they would not be covered under warranty