Recently I had my 2007 Lexus RX 350 (United States) have the front windshield replaced, since my car did not have a heated windshield, SafeLite gave me the option to replace it with a heated windshield. The harness socket was already located under the plastic panel where the wiper arms are located. The technician did connect the harness to the windshield, later that day I turned my de-icer button on to test that the windshield indeed heats up, however, after 10 minutes I found it not heating up. The side mirrors and rear trunk glass heated right up. After checking the manual, I found that the de-icer had its on fuse for the front windshield, checked it, then found it in perfect shape. I know some cars will only turn the de-icer on in variable environments but my RX does not have anything fancy, de-icer button would activate the side mirrors, front (should), and rear glass panels. To test this theory, I started up my 2011 LS 460 and turned on the de-icer, 5 minutes later the front windshield heating elements were warm to the touch, so I knew Lexus does not have such conditions in place for my RX (from my gathered information). My only other untested theory is if power is not being sent to the socket that connects to the front windshield's heating elements, the windshield is defective, or Lexus has a software limitation for US market cars. From my understanding the heated windshield is only for the Canadian market in North America. I will be contacting SafeLite but wanted to get some feedback or thoughts on my theory here! Thank you ahead of time!

 

Not sure if this will help, but I've attached a PDF of the windows section for the RX. At the back of the section, there's a discussion about the electrical connections for the windows. Maybe that may help you figure out what's going wrong. Good luck. Bob

 

It doesn't look like its relevant to the gen 2 RX but I happen have to have posted an engine compartment fuse box diagram yesterday for the gen 3 2010 Canadian market RX that shows where the relay for windshield wiper de-icer is installed: https://www.clublexus.com/forums/rx-...l#post10650071

I'm surprised that the Canadian 2007 RX manual doesn't show a relay for the wiper de-icer - at least I can't find it in the owners manual fuse box diagrams. I would think that a feature that draws so much power would have to be powered by either a dedicated or shared relay. I do see that fuse #6 in the driver side interior fuse box is for the wiper de-icer but you said that you've already confirmed you have it. The engine compartment fuse box for the gen 2 RX appears to be very different than the one for the gen 3 RX.

For what it's worth - or not - here's a link to the owners manual for the Canadian market 2007 RX350 - search it for "de-icer": https://s3.amazonaws.com/lexus.site....U/OM48761U.pdf

Maybe activating the wiper de-icer on a gen 2 RX isn't feasible like it is some other vehicles made by Toyota. I found a thread on a Toyota Sienna forum that documents that plugging in a $14 relay in the engine compartment fuse box of a U.S. market 2008 Toyota Sienna was all it took to get the wiper de-icer to work after, of course, having a windshield with the heating grid installed. Toyota made the wiper de-icer standard on the U.S. market 2011-up Sienna. We've had a 2014 Sienna since new and its wiper de-icer works very well. 2016 was the first model year that the U.S. market RX got a wiper de-icer but it's part of the optional cold weather package.