[Agilix]

Hi everyone, sorry for asking this question using a new post.

I actually asked this couple weeks ago in the sticky thread on how to install Auto-dimming Rearview Mirror.

My questions is about wiring from the power sunroof for some additional installations, such as mirror, camera, etc.

Does anyone have a diagram or pictures for the newer (2014 and up) M3 sunroof wiring? Or has anyone tried the power source from there instead of going through the tedious A-pillar and fuse box route, either for mirror or camera?

I believe the Gentex draws little power and won't labor the fuse for the sunroof, at least that was the case for my old protege5. Thanks for your thought and suggestion!

 

[DougRz]

It appears from this diagram that the 10A sunroof fuse is always live. Along with the cabin light switch which is always live in that console. The CPU appears to be up in the console inside the "motor" box. In which case the B/L (black with blue stripe) wire coming from C-12 to CPU input E would be the ignition wire to tap.

I have a dimming, homelink, hidden compass mirror coming from ebay to install and will be poking around the wiring up there in a few days. I'll update in this thread.

 

[Agilix]

Thanks @DougRz for the diagram.

I am not certain, but if I assume you purchased a GenTex 453 type of auto dimming rear view mirror with HomeLink, you would only need three wires: GND, Always power-on (Hot), and ignition on (IGN) (or just two without hot if you don't want the mirror working when the car is off). The diagram you posted is incomplete, with right side cutting off. There is a B/Y wire for GND directly to Battery (-). Then, the R/W is the hot power line, and the B/L wire is the IGN. I expect you will find all three wires from the harness for the sunroof motor.

I think it make sense. Think about it, the sunroof will not operate when the car is power off. So the B/L as IGN relay is the only possibility (as the diagram indicated "relay"). The only thing I am wondering is why it needs a hot line with power always on (the R/W line).

 

[DougRz]

Full diagram below. Only the ground was cut off. Their wiring makes sense to allow the ignition relay line to be a signal, rather than a power source. There are many items around the car that come on with ignition only, so that line is best a mere signal, else it would be a large current carrier. The mirror, though, is a small load to add. But I will test its amperage draw once installed. The 10A R/W line for the motor need not be relayed since the ignition as signal suffices. A relay toggling on the 10A line via the ignition signal is, I would suspect, a more expensive option than simply togging in the integrated circuit of the motor CPU.

I opted for the later Gentex mirror, the 536, rather than the 453 line. Prices can be low since most ebay sellers think the mirrors are only for the vehicle from which they came. Mine was $50 shipped and was listed as for a Hyundai or Kia, rather than as the later 536. Small demand from owners of that type of car I'd bet. There are $40 453 homelink mirrors on ebay, and possibly $30 as I recall. Or the $30 ones might be the 3xx line.

 

[DougRz]

Finally got to poke around up there and confirm wires are clear and easy to access from the lights and sunroof motor. No problem drawing constant-on or ignition-on power sources. In my case, the existing auto-dimming wiring will be powering my replacement mirror.

 

[Agilix]

Finally got to poke around up there and confirm wires are clear and easy to access from the lights and sunroof motor. No problem drawing constant-on or ignition-on power sources. In my case, the existing auto-dimming wiring will be powering my replacement mirror.

Good to know. Just to clarify: you saw the auto-dimming wiring already exist up in the roof, or you already have a built-in auto-dimming mirror but want to change to another type? Do you need solder to add the wires for the mirror? Thanks!

 

[DougRz]

Good to know. Just to clarify: you saw the auto-dimming wiring already exist up in the roof, or you already have a built-in auto-dimming mirror but want to change to another type? Do you need solder to add the wires for the mirror? Thanks!

I had an existing auto-dimming only and upgraded to the homelink with compass. I needed to solder since the 536 mirror uses a different connector.

 

[Nathan Carter]

Bumping this. Thanks for the info. My '18 Grand Touring came with the plain non-dimming-no-nothing mirror, and now that I've cleaned the garage enough to fit both cars inside, I really miss having Homelink built into the car.

I'm looking at the Gentex series 8; the 80A with Homelink is as low as $189 on Amazon. Or, a used 453 for $30-40 on eBay, that's pretty darn tempting too.

Did you take any pics once you had the top console opened up?

 

[DougRz]

I didn't take photos. The series 8 is certainly nice looking in that frameless setup. One thing to note is the generation of Homelink in the mirror. I learned this after I installed, but older gens cannot handle many of the newer opener security code schemes. My openers use the older purple learn button code, which most Homelink revisions can handle, and thankfully mine did. Just double check.

 

[Agilix]

My garage doors are over 15 years old, so the old eBay Gentex 453 can handle them no problem. Also, since it is so easy to tag the power from sunroof, you can literally change mirror "at your will", if you grow to a new generation later.

 

[Nathan Carter]

Little update: I got a nice clean Gentex 453 from eBay. tested it with a 12V bench source and it works well. It took the programming for my GDO on the first try.

Problem #1 : It doesn't physically fit in my hatchback GT because the mounting stem is too short. The black plastic cover for the tech-package stuff gets in the way, and the mirror physically bumps onto the headliner.
Remedy #1 : I ordered a 1" mounting extension from Amazon. Mito makes one (50-BRKTEXT) but jfc, it's $89.99 for a little block of machined aluminum. I bought a cheaper alternative, the Brandmotion 5000-SPCR for $55, here's hoping it works.

Problem #2 : Everything that I've found in the ceiling console - including the sunroof power - is constant-on, not ignition-on. As mentioned above, the sunroof is 12V constant-on, with the sunroof buttons just controlling relays elsewhere.
Remedy #2 : poke around and find something that's switched 12V; I've read elsewhere that the pink wire to the rain sensor is switched, but there's less room on that harness and under the black cover, and I don't really want to mess with that rain sensor if I can help it. Dome lights seem like a no-go (they're way more complex than just ignition-on and constant-on) but I might look for a diagram just in case. There's also a microphone(or something? I'm assuming it's the mic) up there in the ceiling console.

I might just take the long road and go down the A-pillar, which is what the official instructions say. I doubt this mirror needs more juice than the dome lights and other stuff, but if there were easy things to tap up there, one of the installation manuals would say so.

 

[Agilix]

Odd!

Are you sure you can open your sunroof when the car is in park with ignition off?

There much be a IGN on wire.

Glad you poked and found one!

 

[Nathan Carter]

Odd!
Are you sure you can open your sunroof when the car is in park with ignition off?

Nope. The power to the sunroof switch is always on, but that switch doesn't route 12V directly to the sunroof drive motor. Instead, the sunroof switch just routes a 12v signal (probably low amps) to sunroof drive relays, which ARE tied to ignition (and probably the computer and other things).

So, with ignition off, the sunroof switch can signal the relays, but the relays don't respond unless ignition/computer are on.

There much be a IGN on wire.

There probably is, but after sleeping on it, I've decided to just go down the A-pillar as described in all the "real" Mazda install guides. Gonna hit the dealership today to pick up the pillar clips that inevitably break when removing the A-pillar trim.

[EDIT] I might look one more time for the ignition-on line that goes to the motor, not the switch. It's somewhat harder to get to that wiring harness; even with the overhead console pulled out, the headliner makes kind of a tight squeeze.