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Permanent CR2-12 Window Relay Repair Using Replaceable Relays
This write up is about replacing the CR2-12 NAIS relays found on older generation Lexus and Toyotas located on the window/door lock control switch circuit board under the switches on the driver and passenger front door. As many of you know, over time the contacts inside the CR2-12 relay start failing, causing intermittent open and close window issues which most people believe is the start of a window motor failing (it’s usually not). After researching many posts posted over the years, here’s an inexpensive repair (US$30) that will finally solve this issue. Many thanks to all who have previously taken the time to write up solutions - this fix is based on all of their previous work. This repair has changed over time due to different availability of replacement relays. The best thing about this particular repair solution is that it uses easily replaceable relays for if/when they ever go out again.
The parts listed here are currently (Dec 2023) found on Amazon:
1. 5-Pin Relays with pigtails
(Nilight 50003R Automotive Set 5-Pin 30/40A 12V SPDT with Interlocking Relay Socket and Wiring Harness-5 Pack, 2 Years)
2. Solder:
3. Solder Wick (to remove existing solder):
4. 30 Watt soldering iron.
After desoldering and removal of the old existing CR2-12 relay, here’s the schematic showing which pin holes to wire/solder the pigtails onto the circuit board. IMPORTANT: NOTE THE PROPER ORIENTATION OF THE PIN HOLES BEFORE SOLDERING THE NEW RELAY HARNESS WIRING. THE “TRICK” IS TO VERIFY THE LOCATION OF THE SIDE WITH 3 PINS.
Here’s what the soldered wiring looks like:
Of note, since the pigtail wiring is a much heavier gauge and designed for a greater load capacity, I had to cut off around 2/3rds of the end strands to fit through the circuit board holes.
The off-white plastic protective circuit board cover needs the lip above the existing wire harness trimmed off using a utility knife or Dremel.
After the repair there’s plenty of room to put the new relays behind the door panel:
There are minor steps that I skipped, but based on the pics you can figure it out.
Last edited by dreamalaska; Jan 4, 2024 at 09:55 AM.
Please add a link in the DIY thread. [we don't want the actual post in there].
Since the relays are not plug and play [replacing 1 bad for 2 new], Any suggestion on how long to keep the leads and fitment issues you ran into.
Salim
I left the length of the pigtails as-is to provide enough room for fitment behind the door panel. I think they are around 6-8” long. You could cut the length, but there isn’t a need to do so.
The pigtail wire leads take the place of where the old CR2-12 relay was, with plenty of room to bend the wires 90 degrees to fit under the off white protective plastic circuit board cover.
There were no fitment issues that I ran into.
Last edited by dreamalaska; Dec 31, 2023 at 02:14 PM.
Yes I considered that one. Kudos to the guy making the circuit board and pre-soldering that unit, but the parts alone for 2 doors is US$72 vs $15, and not plug and play replaceable the next time it goes out.
Permanent CR2-12 Window Relay Repair Using Replaceable Relays
