Wednesday, December 7, 2016

RX300 Windows

Victory!  I have been trying to repair the intermittent behavior with the RX300 Windows for a long time.  Even after identifying the bad part there was a struggle to get a replacement.  The trouble is the Power Window Relay in the Door Control Panel.  The Relay is worn out, and is intermittent.  The obvious thing to do, replace the relay, was problematic in that the part went obsolete in 2010, and the remaining supply is pricey.  The original part is a Panasonic CR2-12V Dual 1 Form C Relay, designed specifically to be a power window relay, and PCB mounted to boot.  This is the reworked Door Control Board with the new Power Window Relay.
The replacement is a newer Panasonic ACJ2112, Dual 1 Form C Relay, designed specifically to be a power window relay.  The good news is that this part is smaller, and easily fits within the footprint of the old part.  The bad news is the pin out is not the same, and we'll have to wire the part in, not a big deal.  I searched a long time for this part, and it appears to be the right part for the retrofit.  The large current terminals on the new relay are oriented the same as the original relay when they are upside down.  This means the designers were savvy to the eventual retrofit.  Here is a shot of the original relay.
The original relay is the CR2-12V on the Door Control Board.  The replacement ACJ2112 is to the bottom.  The circuit board had heavy through holes for the relay, but you want to be careful when you desolder the original relay to avoid damaging the circuit traces.  Then I defluxed the board to remove the flux from the solder wick.  I compared the datasheets for the CR2-12V, and the ACJ2112 to figure out the right orientation for the new part, so the wires would go down as straight as possible.  Then use Epoxy to glue new new relay onto the circuit board, upside down, oriented in the middle of the footprint of the original relay.
I'm using two 22AWG Solid Core wires for the connections that carry the window motor current.  The Coil wires are 24AWG Solid Core wires.  I'm gluing the relay down, using solid wire, and making the solder joints as robust as possible in order to withstand vibration.  This is an automotive application, lots of vibration occurs, gotta make it hard.

The passenger side window is the worst one in the case of the intermittent operation.  So it is the first one that I attempted this repair on.  It worked right the first time, LOL!  I carefully thought through the replacement using the datasheets for both the relays, got the wires worked out before I started the operation, and double checked my ideas again during the operation.  Now I have three more to repair, presently.  I bought extra parts to fix more if I need to.  Anyone having RX300 widow trouble?

6 comments:

  1. Thank you for this great post! I too am having problems with the front windows in my 2002 RX300. I've taped over the switches to prevent myself and parking valets from getting them stuck in the down position! I wonder, could you post a wiring diagram for this fix? Or maybe a list of corresponding pin numbers? It's a little hard to make out exactly how you connected the wires in the photos. That would be a huge help to any newbies like my who want to attempt this too!

    Thanks!

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  2. I'm glad my effort has helped. I'll post the specifics in a new post. OK, Thanks...

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  3. RX300 Windows Tech Brief...

    http://black-dog-technologies.blogspot.com/2016/12/rx300-windows-tech-brief.html

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  4. This comment has been removed by the author.

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  5. I had the same problem, got this one on ebay, nice price and fit nice!

    https://www.ebay.com/itm/NAIS-CR2-12V-ACR231-LEXUS-RX300-Window-Motor-Switch-USA-Assembled-NAIS-Relay/182713340549?epid=662344196&hash=item2a8a905285:g:wr8AAOSwTyZZeWxx&vxp=mtr

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  6. thank you very much. You are a life saver

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