1985 Eldorado auto rear-view mirror broke off, mount to roof frame?

[79 Eldorado]

Eric,
The mirror replacement I bought in the mid 90's which looked nearly identical to the one in question was not motorized. It was just like the current auto-dimming technology where they had something on the mirror glass backing. I believe even the original I had from 1984 was the same or similar. It's been a long time but I took the 1984 mirror apart to diagnose what was wrong and it had no motor inside (photo resistor had gone bad). At the time I got the Gentex replacement, mid 90's, I wondered why they were so expensive and so I did a little how it works research at the time. I'm pretty certain I even found a technical paper or a patent explaining them. I will search the net sometime and see if I can find the explanation again when I have a chance.

Scott 

[Elderado]

Here's the inside of my type mirror. Mine's the boxier version. Mine has a motor.

https://www.thirdgen.org/forums/history-originality/539018-auto-dimming-mirror-thread.html

[79 Eldorado]

Hmm... maybe I didn't look at the original in my '84 Toronado close enough. It's late now so I only went through part of the information on the link but it seems to document things well and I believe I stand corrected regarding the comments on my original one. I'm now second guessing the replacement but I do remember seeing the technical document or patent where the method was different but I saw it in the mid 90's. The replacement didn't have any obvious signs anything was motorized or moving. My original never worked while I had the car though so I don't have a comparison point.

I agree with the points made with respect to the force on the puck and the glass resulting from human adjustment as well as it seems like it would not be a common occurrence to break the glass.

Scott

[79 Eldorado]

I found at least the European patent application for the Electrochromatic version without the motor to tilt the glass. This was just the application and not the actual patent. Reading through the description it is what I remember reading years ago (or at least it's the European version). Although what I previously read I don't believe mentioned the sideview mirrors? This application is interesting because in disclosing the prior art they provide what I would call the history of the world in automatically adjustable mirrors... at least history of the world up to 1987. Gentex also had a lot of activity in this field after 1987 though.

Here's some of what is in that application describing the Electrochromatic copied directly from the application:
Improved automatic rearview mirror system for automotive vehicles
EP0285724A2
Inventor: Jon H. Bechtel, Harlan J. Byker
Current Assignee: Gentex Corp
Original Assignee: Gentex Corp
Priority date: 1987-04-06
Abstract
An improved automatic rearview mirror system which is particularly adapted for use with automotive vehicles and which may be utilized as a fully integrated inside/outside rearview mirror system or as an inside or an outside rearview mirror system. The system includes a variable reflectance member (5) the reflectivity of which varies as a function of an electrical signal applied thereto, and the system also includes improved means (18,19,20,21,22) operable to apply an electrical signal to the variable reflectance member to vary the reflectivity of such member as a function of sensed ambient light and sensed glare causing light.

Detailed Description (0024)
In general, in automatic rearview mirror systems embodying the present invention, both the inside and the outside rearview mirrors are comprised of a thin chemical layer sandwiched between two glass elements. As the chemical layer is electrically energized, it darkens and begins to absorb light. The higher the voltage, the darker the mirror becomes. When the electrical voltage is removed, the mirror returns to its clear state. Automatic rearview mirror systems embodying the present invention also incorporate light sensing electronic circuitry which is effective to switch the mirrors to the nighttime mode when glare is detected. However, there is no glass movement, and the change is more subtle than the changes in conventional prism type mirrors. In systems embodying the present invention, the sandwiched chemical layer is activated when glare is detected thereby darkening the mirror automatically. As glare subsides, the mirror glass returns to its normal clear state without any action being required on the part of the driver. In automatic rearview mirror systems embodying the present invention, the mirror darkens in continuous fashion as opposed to conventional two-step changes in the reflectance mode of conventional rearview mirrors. In systems embodying the present invention, reflectance changes from approximately 85 percent reflectance down to approximately 6 percent reflectance, the amount of dimming depending on how much glare the driver experiences. With only a little glare, the mirror dims only partially while with bright blinding glare, the mirror dims to a fully dark condition. The middle range, or comfort zone, is a 20 percent to 30 percent reflectance level that eliminates the most common glare encountered under normal driving conditions while still providing maximum rear vision.

Here's a link to the full document:
https://patents.google.com/patent/EP0285724A2

Scott

[TJ Hopland]

I looked at my 98 Suburban and my guess its its an LCD sort of thing rather than a motor.  This model also includes a compass display in the corner.   I don't know how heavy it is compared to the one in question.    Its mount at first appears to be much larger but if you look close from the outside there is still something about the size of the classic ones that seems to be the main mounting point.  There is something larger that surrounds it and also appears to touch the glass, not sure what that is for.  I wonder if its maybe some sort of antenna?  I think this is pre onstar but maybe its for garage door openers or the keyless entry.

So doesn't appear to be any help looking at a newer one unless its just the weight.  I have no idea if the compass part is self contained or it gets its signal from somewhere else. 

I do remember seeing aftermarket auto dimming mirrors.  Don't remember where, maybe a JC Whittney sort of place?   I remember considering ordering one but didn't like the idea of trying to run the wire so never did it.

[Elderado]

Interesting, thanks Scott.

In the link I added above about the Gentex mirrors I think it mentions doing away with the motor in later models.

By the way, the mount has never broken when I was adjusting the mirror. Always while driving. And I let the button/puck dry for 24 hours before I put the mirror on it.

I'm going to the hardware store today to buy some nuts and bolts for my temporary suction cup fix. If it works for full size DSLR cameras, should work for me.

p.s. I think my motorized mirror is the first generation by Gentex. Which explains why mine doesn't have a quick disconnect wiring connection. As I recall, it's soldered directly to the board in mine, so I can't just temporarily remove it without cutting the wires. Which I don't want to do.

[Eric DeVirgilis CLC# 8621]

I believe the motorized type Auto Dimming mirrors ran from
1985 - 1987 or 1988; Electrochromic version was used thereafter.

[79 Eldorado]

Scott (Elderado),
It’s interesting to read some of the mirror history from that patent application and the link you (Elderado) shared.

I think I got from part of the history at one time there was only a single rear facing photo sensor. The mirror in my 84 Toronado had both front and rear facing sensors. I also recall that it had the multiple number positions shown in that other forum link where-as the one I got in the mid 90’s had only near-far. I don’t remember much more about the original other than one of the photo sensors tested bad and it had a loose Gentex label inside the housing. The label made it obvious who made it for GM. That was the first mirror of that type I had ever seen.

TJ,
I clearly recall seeing it in car magazines as an aftermarket part and if I saw it likely it was in “Autoweek” or “Automobile Magazine” because those are the ones I had subscriptions to. It’s been a long time but I think they were advertising the aftermarket replacements for over $200! I could be wrong but I think before I thought to contact Gentex directly I asked the local Oldsmobile/Cadillac Dealer and I think they told me around $400. I even had a GM discount on parts at the time.
The electrochromatic version was really nice. I ordered my 2003 Sonoma and an option like that was not available but I wanted it based on that 84 Toronado replacement mirror.

Eric,
I think it was somewhere in that time frame as well. They never really came out and said in that link but I was guessing 88 or 89. The patent application seemed to be detailed enough that they had it close to ready but I was basically thinking 1 to 2 years after the patent. There was probably a big incentive to reduce cost of the motorized one. If the motorized ones commonly had issues they probably needed a solution to maintain the business. I can say they were extremely helpful on the phone.

Scott

[Eric DeVirgilis CLC# 8621]

I'll have to check my literature for the model year change to the new
Electrochromic type. I'm fairly certain the older type was gone
by 1989.

Personally I never found the mechanical type to work very
well, even when functioning properly.

Failure was common within relatively short periods of time which
I think was mainly due to breakage of the rubber bands in the unit.

[Elderado]

Ironically, mine functions perfectly. 

[Elderado]

p.s. I contacted a former dealership service manager during the 80s and 90s on the Caddy Owners forum. He said he never saw this happen with the bitten glass.

[TJ Hopland]

While sitting at a stoplight in my Suburban today I observed there are 2 cables coming out of the mirror.   One appears to be the power wires that run into the upper trim.  The other goes from the mirror to that big thing that surrounds the mount.  I wonder if that is the 'antenna' for the compass feature?  In mid 90's tech did you need a separate thing for the compass?   I suppose its not really an antenna, its just where the chip or module lives since you really would not want it  in the mirror since you can change the angle of the mirror independently from where the vehicle is pointed?

Got me thinking I should look to see if those can be had cheap from a pick n pull junkyard.  Just a bonus you maybe get a compass to go with it.   

[Elderado]

Temporary suction cup mount. Haven't tested it yet, but I don't see why it wouldn't work. Windshield is tinted at the top, so basically will be hidden:

image1 by scottcelder, on Flickr

[79 Eldorado]

It's a killer suction cup and would distribute the load well. It seems like the issue with suction cups is they will eventually fall off. So would you remove it after each drive?

I would still favor the puck on glass idea. When you make adjustments to the mirror use a second hand to hold the shaft to counteract the load of adjustment and protect your glass and the puck.

I did finally verify that my 79 Eldorado hard top does have a puck mount so I don't think using one would ever seem out of place. Maybe it was discussed already but did all convertibles use the shaft you pictured or just those with the motorized mirror and then I guess only 1985 since only the Toronado was offered with the mirror in 1984 (and in 1984 the Toronado had puck on glass mounting).

Scott 

[Elderado]

Thanks Scott. That's really just a temporary fix. Great improvement over my current customized wire hanger. Now it will function as a mirror at least. Baby steps here... Based on the reviews etc. of the suction cup, it's supposed to stay put for a long time. How long? We'll find out.

[Elderado]

p.s. I think I might have given confusing or bad info earlier: As far as I know, the factory mount for all 85s regardless of mirror type was a glass puck/button. I think Cadillac used a glass-mounted puck from the early 70s until at least the 2000s. I'd like to fabricate a roof mount that never existed for 1979-85 Eldorado, a flat bent plate that would mount to the roof, hidden under center visor clip. 

[79 Eldorado]

p.s. I think I might have given confusing or bad info earlier: As far as I know, the factory mount for all 85s regardless of mirror type was a glass puck/button. ... I'd like to fabricate a roof mount that never existed for 1979-85 Eldorado, a flat bent plate that would mount to the roof, hidden under center visor clip.

Aha. Ok I understand now. Thanks for the clarification.

Scott

[Elderado]

If I had my druthers, I'd just screw something like this in there:

https://www.caddydaddy.com/1959-1960-cadillac-convertible-interior-mirror-bracket-reproduction-free-shipping-in-the-usa.html

But doesn't look like it would fit the shape in an 85, and I don't know if the 85 convertible roof area could support it/take the screws. And I'd also have to build some kind of T adapter to mount the windshield puck.

[Eric DeVirgilis CLC# 8621]

All mirrors were directly mounted to the windshield glass in all Eldorados of this generation whether hardtop or convertible.

As I see it, the difficulty with the suction device is that it will likely flex whenever adjustment of the mirror is attempted making it difficult to set the mirror to the desired position. Secondly, the cup will likely lose suction over time - at least far more often than if the mirror was attached in the conventional method. Also, due to the inherent springy characteristic of rubber, it is likely the mirror will bob and flutter with vehicle speed and road surface conditions, and there is nothing more distracting than a mirror fluttering about. 

Finally, I cannot see how the alteration will not be visible since the point of attachment is not normally in the shaded area of the glass.

By all means try it if you must but my guess is that sooner or later you'll go back to the original mounting - probably sooner.

[Elderado]

I've tested the suction cup on my glass coffee table. It has a twist-lock feature that tightens it and makes it quite tight against glass. When locked, I can only move the metal puck about a millimeter or two. Hardly moves.

I'll only adjust the mirror once and when I do I'll do it before locking the suction cup down. It might get loose and fall off, but this should be an improvement over my current coat hanger regardless.

Here's the tinting on my bitten windshield. Suction cup diameter is 3", which should fit inside the tinted area. The stock mount arm has two ball adjusters allowing a lot of range, so I think it should work. I'll try it tomorrow and post a picture: IMG_5755 by scottcelder, on Flickr

IMG_5898 by scottcelder, on Flickr