How To replace 124 Homelink Mirror with Frameless GENK80A Homelink Mirror

Overview:

The existing Homelink enabled Gentex/Mito rear view mirror (GENK40A) on the 124 is clunky with a large frame and a trapezoid shape that is wider at the bottom than the top. It is fairly easy to replace this mirror with the newer generation Gentex/Mito rear view mirrors that are frameless and have a trapedzoid shape that is narrower at the bottom than the top. The benefit of doing this switch, aesthetics aside, is an improved visibility to the front due to less blocking of vision from the mirror while also an improved visibility to the rear due to the improved shape of the mirror.

This tutorial walks through the replacement of the existing 124 HomeLink mirror with a frameless Gentex 50-GENK80A HomeLink mirror on a 124 Spider. This is comparatively easy to do with no need to remove any trim, and no need to splice/solder any wires.

The basic steps should be the same if you select a different GENK8 family mirror although I have not installed the other variants myself so do some due diligence first. The main consideration is whether you have the additional wires required by the more advanced mirrors, or whether you need to remove some trim and run additional wires e.g. permanent 12v feed. e.g. if you wish to move from a non-HomeLink mirror to a HomeLink mirror you will need to run an additional 12v permanent power wire to the fuse box or tap into somewhere. This is straightforward to do but does require removal of some trim.

Tools Required:
- T20 Torx bit
- Small screw driver/pin/thing
- Vice or similar for holding an electrical connector while removing wires (optional but helps)
- Male/Female connectors and crimps (not required unless you want to cut off and recrimp new connectors for the mirror rather than reuse the GENK80A connectors)

Notes:
- You can view the available Gentex/Mito mirrors here: http://mito-auto.com/index.php?option=com_virtuemart&view=category&virtuemart_category_id=1
- There is a 50-GENK8A frameless mirror for those who want better visibility but no HomeLink.
- There is a 50-GENK85A frameless mirror that includes HomeLink and also a compass (which in my opinion is not particularly useful)
- This tutorial covers a HomeLink replacement (GENK80A) in an existing HomeLink enabled car. If you don't already have HomeLink then there will be some additional steps to run the appropriate power to the mirror which is not difficult. See Miata thread linked below.
- Acknowledgement to the following thread for information used on the wiring: https://forum.miata.net/vb/showthread.php?t=640478

Part Required:

GENK80A mirror (frameless with Homelink).

If doing a HomeLink to HomeLink replacement then it doesn't matter if you buy the Mazda specific variant or the generic variant. The difference between the two is that the wiring harness on one includes a dedicated fuse. However, other than the connector, we will not be using the wiring harness. The Mazda part number is: 0000-8C-N25. Buy whichever is cheapest. I have bought both versions of the mirror for ~$170-$180 each. I also found one vendor selling the mirror on Amazon via Subscribe & Save which saved me an additional 15%. I bought from Amazon (https://www.amazon.com/gp/product/B00PXGZESO) but the mirror is available from many places.

Time Required:
30 minutes to 90 minutes

Comparison:

Firstly a comparison of the new (left) vs old (right) mirror.



And top vs bottom.



In terms of size the new mirror frame is narrower by about 1 cm (left to right), shorter by about 1.5cm (top to bottom), and not quite as deep. The difference in trapezoid orientation also makes a noticeable difference. However the mirrored surface is larger due to the lack of the frame.

In addition to the size/frame difference the method of connecting is also different. The 10 pin plugs are different and not compatible, hence the need for the tutorial. The old GENK40A mirror connects via a socket built into the mirror whereas the new GENK80A mirror has a short cable attached to the mirror with a socket on the end. The socket is intended to go above the headliner.

Secondly a comparison between the generic and Mazda wiring harnesses that come with the GENK80A mirror. note: I have already removed the end connector from both harnesses. If following my approach for fitting the GENK80A mirror then these harnesses are not used, other than the connector that was removed from the end.



The existing 124 mirror uses a different approach to connect the electrical wires compared to the GENK80A. On the existing 124 mirror the car harness plugs directly into the back of the mirror, on the GENK80A the car harness plugs into a ~6" pigtail harness from the mirror. Also the connector to supply electrical signals/power is different than that of the GENK80A. We therefore need to remove the old connector from the 124 car wiring harness and replace it with the new GENK80A connector. There are three main steps required in order to complete this:
1) Remove the new style connector from the long GENK80A wiring harness (3 wires)
2) Remove the old style connector from the existing 124 car wiring harness (6 wires)
3) Fit the new style connector on the existing 124 car wiring harness (6 wires)

Procedure

Step 1 - Remove the new style connector from the long GENK80A wiring harness (3 wires)

This step is fairly easy once you understand how the pins are held into the connector - they appear to be Dupont/Mini-PV style connectors. (http://tech.mattmillman.com/info/crimpconnectors/). In order to remove the electrical pins you need to lift up the white locking clip (note: it won't come out as the existing pins will prevent it). This can be done with a small flat head screwdriver and the white clip should be able to rise up by a small amount (1/8" or 2-3mm).

To remove the electrical pins you need to release them and then pull the individual wires out from the back of the connector. To release the electrical pins you need a very small flat head screwdriver or similar to slightly push into the front of the plug between the two little tabs and push the tabs apart. This will unlock the electrical pin and allow you to pull the wire and metal pin out from the back of the connector. If you have released the pin correctly it shouldn't take much force to pull the wire out.

The first time I tried this I found it challenging due to not having enough hands - 1 hand for the screwdriver, 1 hand to pull the wire out the back, one hand to hold the connector and then some exclamations as I accidentally closed the white locking clip. I subsequently held the black connector gently in a vice so I could focus on just the screwdriver and pulling the wire out the back of the connector.

If for some reason you really struggle with this step you can just buy a new GENK80A connector for $3-$5. Search for a "12368" connector. I found some listed on Toyota/Lexus parts websites. However I would encourage you to persevere as once you figure out how the locking mechanism works it takes 5-10 seconds to remove a wire. I've done this now on two mirrors as I also fitted a GENK80A to my SUV as I liked it so much.

The following photos should help make it more obvious.

This is the connector once it has been removed. This one has some slight damage to the bottom left connector hole as I was figuring out how to remove the connectors.



If you look at the connector cross section you'll see each hole has two little tabs beneath it. These lock onto the metal connector's "shark fin"



The "shark fin" of a connector




Step 2 - Remove the old style connector from the existing 124 car wiring harness (6 wires)

Disconnect the car battery, disconnect the old connector from the back of the old mirror - to help with this just rotate the mirror a bit so you can see behind it and you'll see a clip to press and the connector will come out.

Now remove the old mirror - to do this you need to loosen the T20 bolt holding the mirror to the windscreen. The hex bolt doesn't need to be fully removed. The mirror should then be able to be removed by sliding it upwards. This old mirror is now no longer needed.

You should see 6 wires going into the connector - if for some reason you have less then you do not have the GENK40A HomeLink enabled mirror and should stop and read the Mazda thread linked at the top of this post as you will need to run additional wires behind the trim.

I had originally planned to extract the pins without damaging the GENK40A connector but I found sitting in the car trying to extract the pins awkward as the pin release mechanism of the connector is different to the one in step 1. It should be possible to extract the pins without damaging the connector. First you flip of the front cap and slightly raise the middle white connector. Then you put a small tool into the front of the connector to free the pins.





Instead I just just a pair of pliers/cutters/snips and proceeded to destruct the connector without damaging the metal pins. Note: the metal pins are delicate and can be easily broken. If for some reason you manage to break one then my recommendation is to just cut the entire connector of where the wire goes into it and then get some dupont style female crimps and recrimp. I had to take this route on the second car I fitted the mirror to and used the following for the crimps: https://www.amazon.com/gp/product/B07DZB8NDW





Once the pins are removed or freed you should have 6 wires (credit to gpb from Mazda forum for the following information/diagrams:

B/L - Black/Blue - Constant Power
BR/B - Brown/Black - Ignition Switch
B - Black - Ground
L/B - Blue/Black - Signals when car is in reverse
B/R - Black/Red - Outside Mirror Dimmer Ground
B/BR - Black/Brown - Outside Mirror Dimmer Power

Step 3 - Fit the new style connector on the existing 124 car wiring harness (6 wires)

The next step is very simple, just follow the wiring guide.



Push the now freed pins into the GENK80A connector. Double check you have the wires in the right holes and the connectors with the correct orientation before you push the pins all the way in.





Once you are certain the wires are correctly inserted then push down on the white locking clip



Step 4 - Fitting and testing the Mirror

Don't worry about tidying up the wires just yet. Fit the new GENK80A mirror to the windscreen using the same procedure as when you removed the old GENK40A mirror i.e. slide onto the bracket and tighten the T20 bolt.



Reconnect the battery and switch on the car ignition. You should see the green power light show on the bottom of the mirror. If this does not illuminate then press the power button on the mirror. If the green power light still does not illuminate then you likely have an issue with the wires you just put together. Recheck them and if still no luck use a multimeter to confirm the wires have the correct signals coming.



Next, making sure there are no obstructiosn to your garage doors, test and program the HomeLink buttons. The quick summary of how to do this is to get your garage remote, hold it by the mirror, press down on the respective mirror HomeLink button (1,2 or 3). There should be a light flash quickly as the mirror learns the HomeLink code and then you can release the buttons. If for some reason pressing the HomeLink button does absolutely nothing then there could be an issue with your constant power wire.

Step 5 - Tidying up

I found that there was enough space behind the top of the windscreen trim to tuck the excess wire and connector behind it without the need to remove any trim.





Step 6 - Test Drive

Now go for a test drive and enjoy the improved visibility



TheSalamander