Back in the early 70s, before the energy _crisis_ when the speed limit had never been reduced below 70, everybody went 90 (and I passed everybody).

Auto air conditioning was a great luxury to have, especially in the deep south on a multi-hour tollway through wilderness with no exits for miles on either side of the pavement.

Of course gasoline was still commonly available with over 100 octane rating for prices less expensive than milk.

And most cars had a regular ordinary V8 engine.

On the typical GM car, AC controls were like this:

https://www.rickscamaros.com/productmedia/catalog_product_ga...

Many drivers never went anywhere without their good buddies "MAX" and "NORM".

And this is what was in a Ford:

https://secure.cougarpartscatalog.com/c9zz-19a884-a.html

Notice how there is only one sliding selector for all the main exclusive functions, each well separated physically and tactically and labeled well. Each company has almost the same identical functions arranged with a similar but not identical order and nomenclature. Regardless each company shows a logical spectrum of functions from left-to-right.

The other continuous slider is for temperature,
and a third slider on an opposing axis for the fan setting (closer to the driver when center-mounted) since that's the one you change most often. Other than the fan, the other settings often remain unchanged across multiple rides in the most ideal expected usage scenarios.

Obviously Max was quite popular with both Ford and GM, and it seems intuitively instinctive as the most cold you are going to get, but it's really just the Recirculate setting, while Norm is for Fresh outside air coming in across your cooling coils, which is what it says on the Ford.

All of this being fully documented in the handy owner's manual in the glove compartment, but even the least technically oriented people usually figured it all out quite easily on their own. Without even looking. If you did have to page through the book at least it was (much) faster than a PDF.

You could say there is very great similarity between both of these major competing control panels, or alternatively maybe there are only superficial differences in these co-operating engineering approaches.

The temperature can be completely set tactically across the entire range with no unanticipated discomfort, even though there is no thermostat, you are simply choosing across a continuous range of what is available under the prevailing environmental conditions.
Which therefore required occasional tweaking en route, on this type of early 70s fully-analog system this critical physical adjustment was most-often accomplished when needed by real-time fine-motor actuation under the direct control of _usually_ natural intelligence. Yeah, there was some total system latency, with largely unavoidable contributions from this type of hardware, but occasionally the intelligence level itself was not up to even average expectations which can add the most noticable deficiency. Some things never change.

On some Cadillacs there was an actual system thermostat handled transparently by the same control panel, and when "digital" there was a fancy numerical indicator but you didn't need to take your eyes off the road to set the temperature as exactly as you would like using the same control panel either.

Well, that's most of the cars on the road having AC, Chrysler/AMC was much smaller and most imports were Volkswagens (without AC) still concentrated in and nearby port cities where there were foreign-car dealers, parts, and mechanics having metric tools. If you drove a Volkswagen micro-bus across a number of states to get to Woodstock in 1969, during most of the trip there was no expected source of repair, tools, or supplies, even tires.

Out on the Turnpike they had some good pavement designed for 100mph along all arcs (even when iced over as often as _that_ happens in Florida) but the regular two-lane roads out in the middle of nowhere were quite wavy after decades of overweight citrus trailers and going 100 on them was like constant air turbulence. It made your voice wavy while the occasional semi was bouncing toward you at 80mph themself. Sometimes when you are in their lane passing one of them simultaneously. The approaching big truck required a certain amount of pavement on your side of the center line since the roads were built when semis were narrower and there was not a lot of traffic out there way back then anyway.

At least the cars were over-engineered for better structural integrity (using a slide rule), but were mostly less capable of precise handling compared to 21st century offerings.

But you really didn't want to take your eyes off the road.

Well that was when Moon landings were a regular occurrence too, so you have to figure at certain times in history you had to be a lot further above average to get very far in engineering or technical areas compared to today.

Even though technology has come a long way over the decades (and centuries) in some ways (in some places) average people themselves were more advanced then compared to now.

A lot more effort is needed to build _foolproof_ systems simply because there are a lot more fools and they are getting more determined than ever.

This of course can be confirmed by direct observation over the long term.

There is still no indication that less-than-natural intelligence will ever be an adequate substitute when performing difficult (but commonly expected) efforts like in the old days. Especially when the natural stuff is trending downward at an increasing rate itself.