Do a web search for RX300 body electrical pdf

It's more complex than I thought it was.

 

also have a look at https://www.clublexus.com/forums/5596711-post11.html

 

Hi, Fruitloops!
My daughter is in college also, and loves her '99 RX. I'm sorry you're having trouble. We had to replace the driver's master window switch, but due to a broken plastic piece. I see them on ebay for as low as $160-170. The passenger side one is a lot less. I would invest in those two switches; they're very easy to replace. I know the amount of money is still significant, but it's a lot less than $1900. If you know someone else with an RX300, I would try out his or her switches on your vehicle and see if that solved everything. I believe all switches are the same from 99-03. Good luck!

 

All windows work, until today passenger side window won't raise.
All light indicators lit. Tried this switch on both driver side and passenger side but the only thing is I can BARELY hear a faint click. Any thoughts are very much appreciated, or links on where to go to show how to clean this switch ?
Thanks!

 

Hello all. I had the same problem with my wifes RX300 were it's like the window and switch have a mind of there own. What I did to fix mine was replace a reley on the PC board which is on the back of the window switch assembly. When I say "reley" I mean a component level reley mounted on a printed circuit board. The parts is about $10.00 that I found through mouser electronics. It's not too bad of a repair if one has soldering skills. I believe I still have the invoice from mouser so if you need the part # for the reley let me know. The $700+ new switch from lexus made me use my electronics training. Thanks.

 

I would buy the master switch thru ebay. Do the search under Lexus RX300 and navigate to Interior then select switches. There are several for under $200,much less than the $600 + the dealer wants.
I would recommend you buy from an established seller with at least a 99% positive feedback rating as well as a return policy. This is where I got my replacement master switch,

Good luck,
Larry

 

There are some great video tutorials on YouTube that show an easy way to touch up the solder connection on the switch & master switch. Its pretty easy to get the switch out and open, and apparently much of the problems described in this thread can be due to the circuit board being stressed from years of "pressing". Quick touch ups of those solder joints may make a stopped window work like new.

 

Nothing seems to work. Jim, could you please explain how you replaced this relay and the part number. Thanks. Might as well give it one last shot.

 

@Fruitloops...I didn't find any source of these relays, including Mouser, Newark, and DigiKey, who used to stock them. However, my window has started working again, so I've postponed further efforts...maybe the sad relays like the cold better.

As I stated in another forum, it seems that one or both of these two relays provide the polarity reversal to change the window between downward and upward motion...and they also appear to me to be way too small for this rather power-intensive duty. Therefore, I'm not at all surprised the relays are charring up on the inside and sticking or failing to contact. That suggests also that we might be able to crack the case and clean them and put them back into service. Pain, but might be workable if we can't simply replace them with new parts.

Or these "H Bridge" relays could be extended off the PC board with a substitute model, preferably one that has a higher power rating for the contacts. Modification for the switch module cover would be likely (i.e. cutting a hole in the plastic cover on the underside in the armrest module, to fit an extruded relay part), but we could deal with that.

Can anyone explain the difference between these two "H-Bridge" relays? I doubt we'd have to replace both of them, and I can't quite tell which one is doing the actual clicking.

BTW, I didn't find replacement parts for either relay. If anyone else has a source for either, please advise!!!

Again, this relay replacement is recommended for the symptom of the window occasionally moving in the wrong (opposite) requested direction. Or perhaps also if the window doesn't move when actuated. (Think of the purpose of the H-Bridge--to reverse polarity of a two-pole motor feed.)

 

Hmmmmm...sounds like the relay under discussion may be the culprit in my little passenger side front window drama. When I put it partially down....then want to put it back up, it decides to go all the way down, then won't go back up. And it gets COLD where I live, folks. I play with the driver master switch for 3-4 minutes and all of a sudden it does go back up, albeit very reluctantly. Being the miserly soul that I am, I have just decided to put the switch lock in play so that the bloody window doesn't go anywhere. I'm too lazy to tear everything down so like all the info posted here so far. Can this whole circuit board be replaced with a wrecking yard used? Or an Ebay edition? Sounds a bit pricey to put in the hands of a dealer.
Because this action/inaction happens with either the master or the passenger switch, the relay circuitry becomes a solid suspect as opposed to either switch, I would think. My 2K is not garaged, so I may wait until next summer to do any experimenting unless I come up with a garage access friend between now and then.