today at dawn
only my driver side is dimming
have a radar with mirror mount

Unplugged my radar and had no change

do you guys only have driver side dimming mirror?

 

Ryan, I have the 3LT, but I have never actually verified the dimming features. Someone will know the answer from experience. However, I looked at both the 2020 and 2021 manuals - it appears to describe the dimming function for only the driver side. But....wait for it ..... the schematic I posted earlier, from the 2020 service manual, seems to show dimming logic in both passenger and driver side.

 

The wiring is likely needed to accommodate both RHD & LHD cars, but you only get one depending. I wonder if the harness is there to add the other?! Might be worth popping the mirror off to check.

 

Been that way for some time on my Vettes. IF you have the passenger side mirror set properly not really an issue with glare!

 

Checked today and confirms JerryU — no passenger dimmer. Funny — I have done a bit of night driving with the C8 and never noticed…

 

THANX for the information. I don't drive much at night anymore, with ANY car, so it would have been a question for me for MONTHS whether it was functioning properly or not.

Again THANX

 

I sent a note to the BlendMount folks today asking if they were aware of the issue referred to in the GM technical bulletin. I received a very interesting response:"Yes we are aware of the issue. We have specific instructions inside the Mirror Tap packaging that says where to tap into and where NOT to tap into. If you tap into the wrong port then damage may occur to your driver mirror. The notice says:

"Be sure to insert the Black Tap into port #3 which houses the Black wire. DO NOT insert the Black Tap into port #4 which houses the Gray wire or damage may occur"

This suggests to me that the BlendMount folks are aware that some owners have indeed mistakenly stuck the ground wire into a port we have not been discussing -- and THAT is causing the mirror damage!

NOTE -- I sent a reply to BlendMount asking whether what they are referring to as "port #3" is the one we're calling "port #8."

 

Those pin #'s don't even match the C8 X1 connector. Are you sure they knew you were talking about a C8? Pin 3 and 4????

Pin 2 is +12V IGN.
Pin 5 is a ground (that claims to be a chassis ground based on schematic)
Pin 8 is a ground (shared with the side mirrors based on schematic)

 

BlendMount’s answer to my follow-up should clear this up.

Right now I do believe they know I was talking about the C8. My guess is what they called “pin 3” is what we’re calling “pin 8.” Pin 8 is the 3rd pin in its row.

You’ve been in there. Is there a gray wire in a port adjacent to pin 5 or pin 8?

I’ll probably open mine up today to have a look…

 

Post 34 shows one side of the connector with a number 5 on it, supposedly a pin number. Are the other pin numbers on that connector, or just 5?

 

Will wait to see their answer and how it compares!

 

Ask and you shall receive. I am now 100% confident hard-wiring my detector to the mirror connections.
======================================== ======================================== =

From BlendMount


This is what's included in the package of the MT-5015

It very well could be the third one over like you said, whichever one houses the black wire is the correct one

NOT the one that houses the Grey wire. Hope that helps.

 

That blendmount picture is wrong and not labeled correctly. Those are not the correct pin #'s, someone misread things and made a bad diagram.

Look at my pic from my mirror:


The grey wire is in pin 9. You can CLEARLY see the PIN 5 molded into the side of the connector so there should be no confusion.

..5 4 3 2 1
10 9 8 7 6

The picture I just posted shows the INCORRECT pins being used, using PIN 8 from the bottom row which is the ground shared with the side mirrors.
I moved my ground up to pin 5 which looks entirely white in the blendmount pic, but you can just barely start to see the black in that pic but much better in my pic. It is the BLK/WHT cable in pin 5 that is a chassis ground.

Sometimes electrical connectors will show you were pin 1 is located. Sometimes they will label the start/stop pin numbers for each side of a connector. In general though, if you know how the #'s are allocated, just knowing one pin you can figure out the rest.
I couldn't see any other pin #'s on the connector, but I could clearly see PIN 5, and that means the blendmount picture is wrong. PIN 5 is on the top row, and if you went with their numbering system, PIN 8 would be the center pin on top with nothing there.

Anyway, their pinouts may be relative only to their own diagram. I would rather stick with the actual pinouts that can be correlated with the schematics from GM.

 

^^^
Yep, their picture has the pins numbered wrong. If you zoom in on their picture you can barely see the 5 in the same location as yours.

 

Thanks. Based on the posts from people much smarter at reading schematics than me... in referencing this pic (accompanying the comments by Blendmount) wouldn't the most appropriate pins to use be: the one with the red wire above for (+) positive and white wire in the top row (far left) for the (-) negative [which many have been calling pin 5] to avoid the mirror entirely (including the ground)?

 

Thanks. Makes the right terminals to use clear. That is what I and most used.

 

Thanks, but I think you are being a bit hard on them. Anybody following their picture, which is quite clear, will be using Pin 2 and Pin 8, which apparently has been a trouble-free approach (as they wrote, it is the gray wire port that is causing damage.) One question still open is why port 7 (gray wire, which BlendMount calls port 4) leads to a fried drivers' side mirror. Thoughts?

I, and I suspect most others in here, greatly appreciate your efforts to help us get this 100% correct. I plan on using Pin 2 and Pin 5...

I am NOT going back to BlendMount suggesting they change their directions to use Pin 5 vs. Pin 8 for the red wire. Perhaps a customer of theirs who is following this thread, and who has the technical expertise to validate your research, can help them improve/correct their installation instructions. I am NOT disputing your findings, but I have zero knowledge in the field of electricity and wiring and therefore I would not presume to advise BlendMount.

 

Sorry, I went back and revised this post a minute after I put it up there. I typed the #'s wrong into the pinout diagram on the bottom row. Anyway, pin 8 ends up in the same position.
Should be:
..5 4 3 2 1
10 9 8 7 6

Take a look at most every molex connector or IDC connector under the sun. The numbering methodology is usually the same.

 

From the blendmount pic, you can see that PIN 5 is actually a BLK/WHT cable.
It is hard to see, but you can see it if you look closely.

 

No, blendmount mentions using the grey wire will cause a problem, probably because it is adjacent to the GND they were telling people to use. They thought that using the red wire and solid black wire would be ok.
GM is saying that using these pins is causing fried side mirrors and they didn't specify it being the grey wire. We have to assume it is the pins that blendmount recommended that are causing issues.

I never said to use PIN 5 for the "red" wire. PIN 2 remains the +12V IGN (switched lead) from VSS.
The issue is whether you use the grounding PIN 8 with solid black wire that is tied to the side mirrors (and apparently leads to them being fried), or if you use PIN 5 which is a BLK/WHT wire that according to GM shop manual schematic goes to chassis ground and is NOT connected to the mirrors.