The day was February 13, 2025. You might have been rushing around to buy flowers, or to arrange a charming dinner date for the following day. I wasn’t, because I sort those things out in advance. Instead, I spent the day browsing the Internet for curios, and came up with the goods. A 1979 Lincoln Mark V with a wiggly little dial, mounted on the mirror of all places. “Mirror dials?” I asked, confounded. “What are these strange contraptions?”
The video came to me from Vanguard Motor Sales, a dealership based in Plymouth, Michigan. They deal in classic American luxury and muscle. They’re also experts at filming a beautiful car in pristine detail. That’s why their video caught my eye, as the camera panned across all the nifty luxuries in the opulent American barge.
Over and above the leather and the chrome, it was those oddball little dials that were wrinkling my brain. Who puts dials on the outside mirror stalk where you have to strain to see them? I realize now I could have just asked the dealership, but I went hunting for the answers on my own instead.
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Lincoln’s Logs
Thankfully this mystery wasn’t hard to solve. Sometimes, it takes hours of research, or if we really can’t figure it out, we ask you for the answers (cheeky, I know). But in this case, I was able to avail myself of the grand Ford Heritage Vault. It preserves documents on the company’s historic vehicles and makes them all available to the public, free of charge. All I had to do was dial up some old Lincoln brochures to find the answers I sought.
What I was looking at was a “illuminated outside thermometer.” Ford had decided this would be the ideal luxury addition to its sedans and coupes. No more would the driver have to stick their arm out the window to feel how hot it was outside. Instead, they could turn their neck to peer down at the side mirror to find out instead. Meanwhile, thanks to the inbuilt illumination, you can determine the temperature accurately whether it’s day or night.
The feature was added to the Lincoln Versailles, Continental, and Mark V coupe in 1978. However, you don’t get a good look at the thermometer until the 1979 brochures archived by Ford. From the wording in these brochures, it appears the option was a solitary dial on the driver’s side, rather than a matching pair on both sides of the vehicle. Further video from Vanguard Motor Sales confirms this. In fact, Lincoln would fit an electrically adjusted mirror the passenger side to avoid you having to awkwardly lean over to adjust it. That’s a proper luxury feature, right there.
According to at least one owner on The Lincoln Forum, finding these thermometer mirrors is incredibly difficult to this day. Not surprising for an obscure option with limited utility, given most of us just get out of the car to figure out how hot it is.
The illuminated thermometer was considered one of the more luxurious features on the vehicle. While things like the miles-to-empty indicator, Cartier clock, and garage door opener could be had standard on Collector’s issue models, the thermometer was more special. It was solely available as an option in 1978 and 1979.In the case of the video above, we’re seeing this feature on a particularly special Lincoln. This example from Vanguard Motor Sales is a 1979 Bill Blass edition, named for the famed American designer. If you liked yachts, cufflinks, and whitewall tires, this was the car for you. Lincoln also worked with a range of other designers, so you could get a Givenchy, Cartier, or Pucci car if you wanted, too. And no—Pucci’s not a typo. Emilio Pucci was just a far less famous designer than Gucci, which worked with Cadillac instead.
Full credit to the team that filmed this Lincoln, too. It takes real skill to capture these fine details so well—had this been a shaky-cam YouTube video, we might never have seen this glorious obscure feature to begin with.
Found Far And Wide
When I first spotted the curious dial, I foolishly did something a journalist must never do. Since I’d never seen one before, something in my brain assumed that this must have been an obscure feature that Lincoln only put on the Mark V in 1978 and 1979. And yet, that was not the case!
Lincoln actually offered this feature for far longer. It just doesn’t come up much, because most people are not as fascinated by obscure mid-century thermometers as I am. The mirror thermometers stuck around until at least the late 1980s on the Lincoln Town Car. By that point, it was pretty much a hangover. When the last of the models with Space Age-style chrome mirrors was phased out, there were no more mirror dials to be had.
Interestingly, I found a rare example of the 1988 Town Car’s mirror thermometer that had been separated from the mirror housing itself. This showed that the light bulb was apparently directly integrated into the thermometer itself. One suspects the heat from the bulb might have influenced the temperature reading by a degree or two. Hardly anything to write home about, but this isn’t home—it’s The Autopian.
As it turns out, Cadillac had these too on a number of models from around 1976—before their rivals at Lincoln, to boot. The Cadillac thermometer was illuminated by a fiber optic strand that ran to the instrument cluster, rather than with a bulb directly mounted inside. This would have aided temperature accuracy by keeping the heat of the bulb away. According to a post on the Cadillac Forums which I’ve been unable to confirm, the drum or barrel thermometers for the Seville were built by a company in Springfield, Ohio.
In Cadillac’s case, the mirror thermometers stuck around until approximately 1982. At this point, Cadillac was shipping vehicles with more advanced climate control which displayed the outside temperature on a digital display in the vehicle. High-tech was very in during the early 1980s, so it made sense that Cadillac eliminated the old-school mechanical thermometers in favor of the newer digital solution.
Unfortunately, in all the years Cadillac was selling cars with these thermometers fitted, they seldom saw fit to mention the feature in their brochures. I only found an offhand photograph of one in a 1979 booklet which showed off the “side window defoggers” with the thermometer just visible in the bottom of the shot.
It’s no surprise this feature didn’t stick around as a mainstay in future luxury models. A side mirror is a weird place to put a gauge, and it doesn’t tell you anything you couldn’t find out just by opening the door or a window.
However, if you must have one, you don’t have to purchase an entire old Lincoln. You can get a stick-on mirror gauge on eBay that is, admittedly, nowhere near as elegant. It’ll cost you about $20. Or, if you’re flush with cash, you can buy mirrors from old luxury cars themselves. A thermometer mirror for a 1988 Lincoln Town Car will set you back about $660 before shipping from one seller, or just $140 from another. A similar part for a 1976 Cadillac Seville goes for $800. It’s not cheap, but I’d love to throw one of these mirrors on an old Miata—just for the bit.
So there you have it! Back in the 1970s, American luxury car designers thought it was useful to put thermometers on wing mirrors for the convenience of the wealthy. Times have changed, and you can now get the same information straight from your dashboard. It’s not as pretty or as frivolous as the old way of doing it, though, nor is there as much chrome involved. Somehow, there’s always something new to miss about the opulent nonsense of the Malaise Era.
Image credits: Ford, Lincoln, Cadillac, eBay, Jurassic Classic Auto Parts, Vanguard Motor Sales via Instagram video screenshot
They were ahead of their time! Yes the placement is weird, but temperature sensors are STANDARD today in many cars. Of course these days the actual thermometer is hidden outside and the temp display is conveniently somewhere on your dash–and can be easily switched to Fahrenheit or Centigrade. Is it useful when you can just open the window and feel the temp outside? Yes it is, specially in colder climates (where you are less likely to just open a window). Based on this info you can better decide what setting to adjust your heater or aircon (or for more advanced models, the car’s climate computer will auto adjust for you). More information is always better.
My parents had an 82 MKVI Continental with this mirror temp gauge when I was a teen, thanks for bringing back the memory!
An incline gauge would be very useful, especially with a powerful engine.
Altitude too, sometimes.
I actually like this. The digital readout on modern cars is convenient and probably more accurate, but this has flair.
I come across those from time to time in my Junkyard travels. I almost grabbed a pair for my LTD off of a Town-Car but didn’t want it to have the Lincoln logo. Knowing their value now I might have to grab em every time!
This illustrates how far we’ve come. My Daihatsu Mira has a digital thermometer plus tons more stuff that these cars didn’t. It’s probably about as fast 0-60, gets 55mpg and costs $8000 usd new. Looks like a nerds shoe though….
“Lincoln would fit an electrically adjusted mirror the passenger side to avoid you having to awkwardly lean over to adjust it. That’s a proper luxury feature, right there.” Proper luxury indeed, just as it was in the 1992 Citroën ZX and 1997 Daewoo Lanos.
Oh how the other half live! My first car didn’t even have interior controls for the mirrors, instead they just had a ball-and-socket arrangement, which you’d adjust by manually shoving the entire wing mirror into the correct position. For the passenger side you needed to enlist a passer-by to do it for you.
My first car was a Rover Metro, so although it also didn’t have interior controls for the mirrors (although the more expensive “S” trim level did have interior controls), it was narrow enough that it was possible to adjust the passenger mirror from the driver’s seat.
Pre digital display, an outside thermometer to tell outside temperature seems logical. Knowing when the roads might be frosty seems like a reasonable thing to know. My Prius sho that.
Please explain the outdoor tachometer.
Hood mount tach? Simple, the parts bin cluster doesn’t have one, and it’s only going on a small number of high dollar performance cars. Just bolt a big one to the hood!
If I had to guess, the most practical application of the thermometer is telling you if you’ve hit that point around 7C/45F where apparently the roads get a bunch greasier, and accordingly to drive more carefully (similar to the sort of cold warnings modern cars give)? Not like you can get that by sticking a hand out the window (or my personal thermometer isn’t that finely tuned at least).
Were the thermometers mercury-based? Makes for an interesting crash/safety concern. (And on second thought, I guess I’d be disappointed if Ford/Lincoln/MERCURY brand didn’t use mercury-based thermometers).
Bi—metal spring I am sure.
My parents had a Seville with one of those. When they bought that car they pretty much checked every option box. Thermometer, faux convertible top, 4-6-8 engine. It was a terrible, and terribly overpriced, car and the last American car they ever bought.