Greetings- Own a 2000 RX300 (original owner). Planning to sell the vehicle and one of the issues that it's had for a few years is intermittent window operation. Finally decided to attempt to get this repaired by replacing the Master Window Switch. Here's where it got fun:

* Replacement Unit 1: Purchased from E-Bay. $75 The pins in the connector were too big thus the plug would not fit. Returned for a refund
* Replacement Unit 2: Purchased from E-Bay. $85 All windows worked correctly EXCEPT the drivers side. Returned for a refund
* Replacement Unit 3: Purchased from E-Bay. $85 Everything worked great but after a few days of sitting the battery was drained. Determined the unit was causing some sort of short. Returned for a refund.
* Replacement Unit 4: Purchased from E-Bay. $80 Works great but I'm still getting a battery drain after a day or two. Have not returned this unit yet.

All of these replacement units were new and all from China and from 4 different sellers. Even though the e-bay sellers are listed in the US ....... the parts are all from China. That's their latest trick into trying to disguise where the parts are located. I know this because all of my refunds came from Chinese accounts. I'm not all anti-china ... just pointing out the facts.

So I'm now assuming one of these Master Switches has done some damage electrically to my system. The next step was to determine if I had a parasitic draw. Sure enough ....with the Master Switch disconnected there is no draw. Attaching ANY of the two I have in hand (including the OEM original) results in a parasitic draw.

I'm hoping anyone might have some suggestions to move forward or an electrical diagram handy. I did pull all of the fuses while checking current in case that solution comes to mind. Nothing came of that .... thanks !!!

 

Just to put this to bed ................ I've determined that my problem was simply another bad Master Switch that was causing yet another parasitic draw. These E-bay and Amazon sources of these units are all getting them from China and from the sounds of it .... most of them will cause a parasitic draw on your battery. I've ended up buying a good used OEM unit from E-bay instead.

What got me on the goose chase was incorrectly diagnosing that the original OEM part was also draining the battery but upon plugging that one in again .....it actually wasn't. Gotta make sure when testing for a parasitic draw you give the car enough time to "go to sleep" between pulling fuses, harnesses, modules etc.

In the end I went through (4) of these Master Switches from (4) different suppliers and none of them worked. Buyer beware .....

 

Thanks for letting us know about the inferior parts. I had the intermittent window switch issue on both front windows as well. I too went the eBay route and lucked out. My research here and elsewhere shows that it is a bad relay that causes the issue. I did not feel adequate to attempt the repair that I found.

 

Yes .....a bad relay is what typically causes this problem. I was considering replacing just that at first but then realized for not a lot more money but a lot less effort, one could simply spend $75 and get an entire new unit..... which of course led me down this rabbit hole.

I will indeed go this route if the used unit shows up and doesn't work.

Thanks for the reply ....