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
Dad’s Seville had one. It was helpful on cross-country trips, for determining whether or not you needed to grab a jacket before making a pit stop.
OMG! Vanguard wants 70K for the 1979 Lincoln Continental! 🙁
(It has 10,278 on the ODO!)
It appears that Lincoln one reads up to 120 F. That’s some fine future proofing there!
Interesting I knew about Cadillac using these but forgot Lincoln did. I wonder if GM put these on Buick Electras
And yet no one here was disappointed when Emerson, Lake, and Palmer did NOT start playing in the video?
Honestly – they show everything else on that beauty functioning as designed, but refrained from showcasing the actual 8-track they popped in the dash?
Take all my money and give me that land yacht!
I am always surprised when someone discoveres something that I thought was common knowledge.
I’m not that smart, so I figure if I know something, everyone has to know that same thing
It reminds me that my knowledge base is weird. Reason 82 why I love this site
“ One suspects the heat from the bulb might have influenced the temperature reading by a degree or two”
The new thermostat in my house has a very nice illuminated display on it. If you leave it with the light on it never gets below 16 degrees C. Utterly stupid.
On the other hand the additional complexity of having to turn the display on means that no one else knows how to turn the heating on or mess with the temperature. My other half thinks heating should be on in the winter and off in the summer, whereas I think it should be in when it’s cold and off when it’s warm. With the new thermostat logic has finally won.
The 18.3 reading on the Cadillac MPG Sentinel was, of course, with the engine turned off.
My grandfather had a Sedan De Ville when I was a kid, and it had that early 80s blue LCD screens on it for various features including the real time MPG counter. I have no idea why they even installed those. It was like a pinball machine bouncing around. He’d give it gas from stop at a green light, it dropped to 3 MPG. He take his foot off the gas to coast, and it would jump to “99 MPG”. Even cruising on the freeway, it would constantly be jumping around anywhere between “10” and “25”.
“…it doesn’t tell you anything you couldn’t find out just by opening the door or a window.” You obviously do not understand how the wealthy live.
Yeah, you have your butler get some expendable lackey put their arm out of a window.
It’s like in that Snowpiercer movie where they make you stick your arm out the window as a punishment.
That is literally half of Alexa’s reason for existence in my home.
Think of the digital assistant jobs!
Had a geography teacher in my high school who used to ride one of those Honda 125cc step through bikes, and he had an ordinary alcohol thermometer wired to the handlebars on one side and a humidity dial wired to the other. Wired with fencing wire, not wi fi…
The image is a bit confusing, no?
Agreed, not sure if they intended to use a Cadillac thermometer on a photo of a Lincoln?
I dunno, having a thermometer is a fantastic feature which every car has nowadays, and it’s much more useful, and precise, than sticking one’s arm out the window.
Its placement might have been unique but surely this wasn’t the first or only air temperature thermometer put on a car?
My late Father owned a succession of Lincoln Mark cars starting in 1969 with a Mark III and only ending in the early 80’s when he upgraded to Town cars. As I recall at least one had this thermometer and he would announce the temp any chance he got. We all thought it was weird. The Mark III was a beautiful dark blue with a white top and all white (leather?) interior. If I could find one today I would buy it.
Peak dad behavior, right there.
Yep, trapped into a mundane existence of provider, looking for any scrap of change in life, hoping the others in his clan will follow in a newer direction, one time, and if only just for one brief moment, at his behest.
Grandparents had one on their 88 Town Car, always thought it was a ‘cool’ touch
From a 2025 perspective, when all cars have digital displays and electronic temperature sensors are dirt cheap, this makes no sense. But in 1979 those bits would have been ridiculously expensive. The side view mirror placement is perfect. It’s outside, but easily viewable from the driver’s seat. The whole thing probably cost the manufacturers pennies to build but was a $50 option. Brilliant all around.
I like having a gauge to tell me if its likely to be icy. It pretty common to drive through a few degrees of temperature change and ice really fucks your day up if you aren’t expecting it.
Of course with a gauge in just Fahrenheit I’d have no idea what the critical temperature is.
Ah man, so my uncle currently owns the exact same spec Mark V, colors, fake convertible top, exterior temp dial and all – and it just sits. I could probably just ask for it and get possession at this point, but man it gets more and more tempting. Anyone have experience actually working on and running these yachts?
Yep, they’re fantastic, easy to work on, parts are cheap and plentiful. Don’t expect either speed or fuel economy, that’s not what they do. They’re so comfortable you’ll wonder WTH is wrong with modern cars. And of course they now look like nothing else on the road. As affordable classic weekend cruisers, they’re hard to beat.
If it has the 460 it’ll get out of its own way, but definitely not what I’d call fast.
Vacuum, emissions systems and finicky carbs are probably the worst things. Aftermarket fuel/air delivery and bypassing emissions equipment is probably the way. I say go for it, they’re good looking things.
My mom had one and the carburetion was never right the whole time. It was in the shop over and over for low speed stalling and stuttering.
That’s my normal experience with carburetors. I always blamed it on driving non mainstream cars. Maybe it was the carbs after all
Happily most of that stuff is easily fixable, especially once they’re past the age where you need to worry about keeping all the emissions stuff working. Just getting the distributor re-curved and setting timing to pre-smog specs does wonders for these engines. Same deal on the carburation. The Autolite carbs were probably the worst of the big three, but happily they’re just square bore carbs – just replace the thing with an Edelbrock 600 CFM electric choke (don’t forget to get the Ford kickdown linkage kit with it) and you’re good to go.
The other mod that really helps with fuel economy and highway drivability that I did to my car was to replace the 3 speed C4 automatic with a 4 speed AOD with the lockup torque converter. The AOD is not electronically controlled, and I was able to modify the kick down linkage from the C4 to act as the TV rod to control the AOD. It got my Cougar up past 20 mpg highway with the 351 Windsor and 4 barrel on an iron 4 barrel truck intake. I can’t suggest that swap with confidence in this case because the Lincoln will have a 460 with a C6 and the big block bell housing pattern, so I don’t know if a similar late-model OD trans swap would be as easy in that case. (Swapping the C4 for the AOD was so easy I didn’t even have to change the trans crossmember or driveshaft length.)
Looks like we’re on the same page. I’d also consider upgrading the cam and maybe the heads, even if it’s just stiffer valve springs
With modern parts to upgrade pesky 1970s engine tech, these can be fun old cruisers to take out and bring some smiles to car-nuts’ faces. They’re comfortable on trips, have trunks which can swallow remarkably large amounts of stuff, they’re ridiculously long, and are basically good at converting gasoline into the sort of fun that appeals to those of us who like older now-oddball cars. Go for it.