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I was not aware of that much older thread on the same exact style DIY-- Good find! A lot of people commenting in there, including SupraTico, are OG members of this forum and SupraForums.
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T2d2, at the end of the day really doesn't matter what my reasons for also expressing interest in this compass-infused mirror swap DIY are or what your reasons for feeling it's ultimately not useful are... this is a thread intended to explore possibilities for installing some kind of compass-- specifically just a compass be it digital or analog from an some OEM or aftermarket part-- into an SC300/400/Soarer.
Personally I do use my phone's map navigation program when I need to and I do sometimes use a standalone Garmin GPS navigation device. But I don't always want to use them and in some instances I actually do just want to see a simple compass heading at a glance while I'm driving-- for whatever reason I may have to do so at any given moment. I am not interested in what my appliance smartphone can do for me in this regard-- I hardly touch it while I'm driving. I am interested in how to add the specific compass feature as a constant solid state function to my SC so that the information it provides is constantly available whenever I happen to feel the need to take note of it.
You did ask why anyone would really need or want to look at compass or temperature readings in a moving vehicle and I gave you some legitimate ones, then you gave your list of reasons and scenarios which apply specifically to you, your SC300 or your pickup truck as to why none of those reasons are what you consider reasonable enough to validate someone else's need or want for a simple built-in compass function in their SC.
It's fine if you are not personally interested in adding this to your SC or your pickup truck or feel it's not a useful effort but cboog3105 and I and others in the decade old thread on the same subject that he linked do and adding it to an SC300/400 or Soarer is what we're here to figure out how to do.
There are plenty of GPS options available from standalone navigation units to smart phone GPS/map nav programs to 1-DIN and 2-DIN aftermarket stereo head units with GPS navigation built in and/or an Apple CarPlay or Android smartphone interface and there and there is also no requirement for any SC owner to add a hard-wired/mounted compass device, or use any of these other various GPS-based options.
The point of this thread is to find solutions to installing a compass into an SC regardless of why someone might want to and to this end I think we have hit upon a very good option with the GS mirror that will work out very well. Let's keep things on topic and prove that it will work as a DIY that other member-owners can use for their own SC's if they so choose to.
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I've been busy in the last couple of days but I'm going to see about double checking the pinouts on both my spare SC auto-dimming mirror and the GS auto-dimming mirror with compass as well as opening them both up to determine if it is possible or not to fully swap the internals of the GS mirror into the outer housing of the SC mirror.
I found something else that will be useful-- an old thread containing the auto-dimming mirror pinout for the 1998-2005 GS!
First, for reference here's Arsenii's post from a couple of pages back with both the SC300/400 auto-dimming mirror and the IS300 mirror pinouts:
Originally Posted by Arsenii
Figured I will help you out a bit with the homework..
From wiring diagrams, it seems like the compass doesn't require anything special, meaning that the unit is self contained, and only needs power coming in, just like a factory mirror. Below are pinouts for both connectors, which does contain an unpleasant surprise with Ground being flipped from Pin 2 to Pin 4.. 12V is the power from Ignition, EC+ and EC- are there for for Electrochromic element in exterior mirrors. though pre-facelift SC300/400 didn't have dimming exterior mirrors, so they won't have those.
Other problem is that the male and female pigtails got flipped between IS and SC, so it is not even possible to just swap out connector housings. I am not sure what's inside of the SC mirror, but judging from pictures in a linked thread, IS300 has another connector on the inside, which is a generic one found in most electronics, so it shouldn't be that difficult to make an SC wiring work with the IS mirror, replacing the internal housing, if there is one that is..
Hope this helps and best of luck!
Edit: After inspecting all the wiring and installing the modified GS mirror myself without changing the wire layout and after seeing cboog3105's result with no wiring pin location changes I do not think that the above pinout diagram for an SC300/400 mirror is correct. Further, all the wire colors are in the same locations on the SC300/400 mirror connector, on the 98-05 GS mirror connector and on the IS mirror connector even though it has the wrong style housing and the wrong type of terminal ends.
And here in this thread post from 2006 is we can see the 1998-2005 GS mirror pinout:
And here's the pinout diagram from the 98-05 GS wiring TSRM:
So this shows us that the IS300 mirror (which has the wrong style pins and which would need to be modified with a new GS or SC style connector with pigtails) and the GS mirror have the same pinouts while the SC300/400's 96-00 mirror connector pinout has its EC+, EC- and Ground pins in different locations.
Edit: I now suggest leaving the pin locations alone as there seems to be no reason to change them after all.
Therefore to change the GS mirror connector pins around for SC300/400 compatibility we should therefore move:
EC+ at Pin 2 to Pin 3
EC- at Pin 3 to Pin 4
Ground at Pin 4 to Pin 2
The +12V Switched Power at Pin 1 stays at Pin 1
For anyone using an IS300 rear view mirror either some SC connector pigtail with wire changes and splicing would be needed or that internal cable connector would need to be swapped for one from an SC with the pins similarly rearranged if tracing and continuity testing each wire on the cable still reveals the EC+, EC- and Ground wires being in the wrong locations at the connector. Hopefully in that case the circuit board will identify each signal on its surface to avoid any confusion.
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Now as for the SC300/400 and GS 98-05 mirror connectors themselves, I have examined the casings of both and they are physically identical and both carry the same "11187" embossed part number. The only difference is their color.
This means anyone can buy this connector at a Lexus or Toyota dealer with P/N 90980-11187. Cost is around $5-$7 for one.
And the x4 82998-12420 terminal repair wires for that connector can be bought from either type dealer for $6.50-$8.50 each.
That should help anyone who wants to do some extra work (wire splicing, soldering and heat shrinking) to get an IS mirror working instead of the much easier to adapt 98-05 GS mirror which already has the correct connector and wire terminals.
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From an old thread post of mine detailing the entire SC rear view mirror removal procedure IF your mirror mount has been glued in any way by before you got your SC: https://www.clublexus.com/forums/per...l#post10169165
A Torx T30 bit is required to remove the holding screw. Do NOT use a hex bit or Philips screwdriver or you'll strip it out, and possibly cause an issue safely removing the mirror from your windshield!
Here's the parts list to for the SC300/400 mirror mount system at the windshield glass. Order as needed:
87817-24010 — x1 Mirror Inside Spacer (Metal inside suspension)
87825-24010 — x1 Mirror Inside Spring (Metal "U" Spring)
87808-24010 — x2 "Mirror Inside Holder" or "Holder Sub-Assy" (Ball Bearings in casings)
87853-24020C0 — x1 "Base" (Outside trim piece between mount and glass. Says to order by interior color)
90148-60018 — x1 Screw, Hex Lobular (Rearview mirror screw)
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Now to see how easily both cases are opened and if the guts of the GS mirror can swap right into the SC mirror housing for a perfect interior color match...
Last edited by KahnBB6; 04-20-22 at 01:47 AM.
Reason: Revised some crucial wiring pinout info after testing and inspection
To check if auto-dimming mirrors work, cover the sensor on the back of a mirror, and shine a light on its face, see which mirrors would dim with both the new and the old mirror connected, just out of sheer curiosity..
just ran the check and auto dimming seems to be working with both the original and the gs mirror plugged in
though my drivers side mirror doesn't like being in night mode
Wow! After all this time I wasn't aware that the SC got auto-dimming side mirrors I thought memory position and heating in addition to standard motor adjustment were the only special features (and of course power folding mechanisms on the JDM Soarer models).
There is a way to repair that glass back to normal. I don't know how to do it myself but there are repair companies that will. Not promoting them but after a quick Google and Youtube search I found Radar Mirror for instance. They focus on rear view mirror auto-dimming repair but it seems to me that the same technique involved could work on side mirror glass as well. There are other companies out there that will do the same.
It took some careful modification with a Dremel to shave down some notches in the SC mirror housing to match the same shapes in the GS mirror housing and the screw holding the ball of the GS mirror mount in place was impossible to get out without breaking it and the internal mount but I was able to successfully swap (in the SC mirror housing this same screw came right out easily!) but I was able to transfer everything inside the GS compass mirror assembly into the modified shell from the 96-00 SC auto-dimming mirror with a darker shade of tan that matches my SC's factory tan interior.
Opening both casings with a small screwdriver took a little finesse at first but was surprisingly easy. Unlike VERY early 90's Toyota/Lexus rear view mirrors with no electrical functions inside them these mirror housings were not glued and were intended to be opened up for service.
The only external(ish) part that I needed to carry over from the GS mirror was the plastic for the front button due to the catch that the SC's auto-dim switch is pressed in a slightly different location than on the GS board. I could have shaved and modified part of the SC auto-dimming mirror button for an absolutely perfect color match but I just didn't want to sacrifice the plastic should I ever need to swap it out in the future. It's a hardly noticeable shade difference in such a small area.
I will say that this was more work to do overall. If having an absolutely perfect color match for your interior is not of interest it is fine to just remove the mounting arm from an SC mirror (the plastic thing around it has a tiny little catch to undo-- don't yank it apart!) into the GS mirror housing after removing the GS mounting arm.
Hopefully others will not encounter a seized screw holding in the GS mirror's rotating ball section as I did. I even used a screw extractor kit on it after stripping it from effort and it just snapped off in my case. Again, the SC's mounting arm was a piece of cake to remove.
With the GS mirror's connector I took a picture of the wire arrangement and de-pinned the connector temporarily to snake the wires through the pass through holes of the metal mounting arm. I then re-pinned the connector after it was fully separated from the arm.
I took a quick length measurement of the wire harness coming from the SC mirror's connector and made sure the same length of harness wire to the connector was replicated with the GS harness upon reassembly of all the components.
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Also, the EC+ and EC- I discovered have to do with auto-dimming functions for the side-view mirrors. For SC's apparently those were not introduced until the 1996 model year (someone correct me if I am wrong about that). This explains some of the different variations of mirror wiring harnesses that I encountered a few months back when I disassembled a couple of side mirrors to swap housings over with my car's original 1993 mirror harness. Now I understand that the SC 1996-2000 auto-dimming mirrors apparently worked in conjunction with auto-dimming side mirrors either as standard or as an option.
My 1993 model doesn't have those but now I wonder if the EC+ and EC- wires were populated through the rest of the chassis on 1992-1995 SC300/400's.
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I'm confident that the actual work of this DIY swap went well but sadly in my case I was not able to get my used 98-05 GS mirror's compass working. It powers up and auto-dimming appears to work but the little green light either stays constant or flashes before turning off unless I hold down the button and release it. At startup the compass shows all symbols lit for a second and then reverts to two dashes.
After reading the calibration procedure for these mirrors (will include in my next post) and trying it in every way possible after driving around in several directions and after driving in a circle several times in a parking lot I was unable to get the compass to change from the "--" two dashes.
I consider this project to be a good effort but it looks like in my case I'll need to find yet another used GS compass mirror or find another from some other vehicle with the same or similar Gentex internals that will go right into the housing.
It sucks that I happened to buy a dud mirror but we did prove this custom swap to work!
I may leave this malfunctioning mirror in or I may reinstall the SC auto-dimming mirror I had in the car.
Also, the EC+ and EC- I discovered have to do with auto-dimming functions for the side-view mirrors. For SC's apparently those were not introduced until the 1996 model year (someone correct me if I am wrong about that). This explains some of the different variations of mirror wiring harnesses that I encountered a few months back when I disassembled a couple of side mirrors to swap housings over with my car's original 1993 mirror harness. Now I understand that the SC 1996-2000 auto-dimming mirrors apparently worked in conjunction with auto-dimming side mirrors either as standard or as an option.
My 1993 model doesn't have those but now I wonder if the EC+ and EC- wires were populated through the rest of the chassis on 1992-1995 SC300/400's.
The auto-dimming rearview and side mirrors were introduced at the same time, and as far as I know were standard. The rearview is backward compatible, but the sides are not, as they use the bigger 2-row connector. When I bought my '98, the driver's mirror had been replaced with a '92-95 one, presumably because '96+ ones with good glass are a lot harder to find, and the wiring hacked up to tie in the basic heater/adjustment functions on the mismatched connectors.
The auto-dimming rearview and side mirrors were introduced at the same time, and as far as I know were standard. The rearview is backward compatible, but the sides are not, as they use the bigger 2-row connector. When I bought my '98, the driver's mirror had been replaced with a '92-95 one, presumably because '96+ ones with good glass are a lot harder to find, and the wiring hacked up to tie in the basic heater/adjustment functions on the mismatched connectors.
Sadly even though I hoped a bit I suspected this would be the case. Thank you for confirming! Since the auto-dimming side mirrors are likely a used-only item at this point in time it's probably going to be a thing to get their special glass reconditioned in exactly the same way auto-dimming rear view interior mirrors are restored.
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Regarding the malfunction of the GS compass mirror I purchased, it kept ******* my mind that there must be *some* way to diagnose the issue on the circuit board and get it working again. Replacing capacitors maybe?
Or perhaps something more drastic such as what this repair tech demonstrates on a GM mirror with built in compass that looks very much like the some of the newer Gentex models:
To help out anyone doing one of these IS, GS or other OEM Lexus rearview auto-dimming mirror with compass swaps, here is some documentation on how to do the calibration procedure.
Since the Earth's magnetic field is slightly different depending on where you are located around the globe there are several "zone numbers" established to allow you to tell the internal compass electronics to adjust and compensate so as to accurately display your true magnetic direction.
The only thing I did not find much help with is if your OEM compass mirror is stuck onto displaying the two dashes ("--") no matter what you do. That seems to indicate some malfunction as was the case with my mirror (for which I'm investigating whether or not it can be fixed). For cboog3105 however there was no such issue and his used compass mirror seemed to work right away after plugging it in-- probably only a quick check of the calibration is all that should be needed in his case.
1. Set the zone by holding "Auto" until a number displays.
2. Select zone by pressing the "Auto" button until you find your region.
3. Number will disappear.
4. Drive around in a cirlce at about 5 mph until "cal" disappears.
5. If unable to drive in a circle, drive around the block.
Zone reference picture below (ignore the VW Toureg parts):
And here's a much more comprehensive guide which details both the zone setting calibration or the manual driving in a circle style calibration:
I think you're good so far! It has been some months since I worked on mine. Take a look at the parts list I left above and my notes. It is pretty much as you saw-- there was a little modification needed to fit the GS mirror internals into the SC style and color housing. VERY careful application of a Dremel in specific areas did it for me. Test fit MANY times as you gradually and carefully remove only the plastic material that you need to.
If you want to use the GS mirror casing then you MUST swap over the internal mounting arm from the SC mirror. I recommend that you just re-use the SC mirror casing and follow the Dremel trimming guide above to fit the circuit boards and other parts from the GS mirror into the SC mirror casing. There is a little black round plastic clasp thing that goes around the mirror ball inside. There is a little catch to undo it if you have to (but you shouldn't have to). Don't force that thing open any other way or you'll break the other side of the plastic round clasp thing. Best to leave that part installed with the SC mirror casing.
Then just follow the electrical pinouts above to swap the wires over. The GS connector will need to be de-pinned to remove it from the GS windshield mount. If you're familiar with how to de-pin and re-pin Toyota connectors this will be easy.
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In my case unfortunately I seem to have bought an electronically defective GS mirror. But everything I did with the wiring, installation and calibration was exactly as has been described by others who have done this in SC's and other models.
I plan to buy another GS compass mirror to swap in to my modified example when I get a chance. Or possibly send in the finished mirror unit to a repair facility if an electronic fix is available for these. Sometimes when you buy an old used part you might get something that doesn't work quite right.
I know what needs to be done... I just haven't done it yet. My conversion I am confident in. I just bought a faulty compass mirror unfortunately. Luck of the draw.
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Wishing you luck! It's not too crazy of a project. Just a little tedious. Go slow and take your time.
04-18-22, 10:35 PM
I thought memory position and heating in addition to standard motor adjustment were the only special features (and of course power folding mechanisms on the JDM Soarer models).
