The first ''Rear-only warning’’ AeroDynic 24 MEAH-T


Veteran Member
Hi folks!

As the title suggest, this baby would be the first (as far as I know) AeroDynic to perform rear-only warning. I was always impressed by the beautiful design of the Aerodynic. I loved the option to change the pattern to whatever one would choose, the endless domes configurations, the many variations of the Aeros… Yet I still wondered if it could get to tweak it a little bit more.

-Before going further, please pardon me if this description is a bit lengthy, but I figure you people will be curious as to how it was done. If that’s not your cup of tea, just scroll down to the good stuff. Because of course, there are videos.-

When the Jetsonic came, a few years after the Aerodynic, it had a few interesting features, like the front cut-off option (Basically a mirror across the front and the back of the bar) and the intelligent flashing rotators. While the front cut-off was never an option for the Aerodynic, I told myself it didn’t have to stay this way. Inspired by the front cut-off capability and the stop-and-flash of the Jetsonic, as well as the Select-Alert feature of Code 3, I somewhat combined all 3 to modify a 24 MEAH-T Aerodynic to be able to perform the rear-only rotating function.

The JetSonic’s stop-and-flash function worked with a properly timed cam switch on the motor assembly. It stopped the rotators at a precise position and then flashed them. Code 3’s “Select-Alert” used multiple contact plates and diodes to continuously rotate the pods, yet only lighting them when facing the rear of the bar.

Since the motor assembly of the Aerodynic is aloft over the frame, and since I didn’t have the room or the proper Jetsonic assembly to add said cam switch, I went another way. I made a custom cam switch holder out of thin brass sheet, and secured it under the idler gear of the outer rotators on the driver side. I then made a wooden cam to activate the cam switch, secured in place under the idler gear with the 2 availables holes of the gear. The brass/switch assembly was then screwed to the frame under the gear, using the mounting plate screws, so it would not be apparent from outside of the bar nor would it interfere with the rotators.

It basically works like the Select-Alert function of Code 3, but with the cam-switch method of the Jetsonic instead of Code 3’s contact plates. It cuts off the light while the rotators faces the front of the bar. You only need to correctly time the idler cam-switch in regards of the rotators.

Now a problem caused by this method was the insufficient time for the bulb to cool down, hence still projecting a weak flash to the front. Installing a 50watts, 8 ohms resistor in line with the motor when the cut-off function is activated was the solution. This performed 2 tasks:

-1: it slowed down the motor to allow the bulbs to be dark enough to prevent weak flashes when the rotators are swinging to the front.

-2: it gives a slower warning pattern to the rear. I am in no way related to anything LEO, but if I read this board correctly all those years, it seems to be commonly agreed that the rear warning should be a somewhat slower and coherent, rather than an “anything goes” signal.

The 2nd downside to this homemade modification is the limitation of patterns available. Because there is only one cam, the rotators all have to face almost the same direction to allow the cam to be effective and the reflectors to cut the front light. I chose the short outside-in pattern 2-0----0-2. I know this bar would never see service, but I tried to be as thorough as possible. A little “what if” thought, regarding design, for if we were still in the 1980’s.

That being said, let’s get down to the wiring. I won’t get too much into the details, but I added a 2nd terminal contact and a custom terminal holder to manage the necessary additional relays and diodes to properly isolate the motor and lights. I also wanted the takedown lights to flash like the LAPD flashing takedowns, triggered by the Code 3 flasher. I did not have one on hand, nor the space to squeeze it in the bar or add another can flasher. So I added 2 relays at the end of the bar to allow the takedowns to flash in a X fashion with the rear amber flashers. It is activated by the 3rd position of the slide switch and powered out of the single rear amber 537 can flasher. If the takedown toggle switch in flicked on, it overrides the flasher and activates the takedowns while letting the rear amber flashers do their thing. Finally, a simple toggle switch activates the rotators front cut-off option, via a speaker wire. I was getting short on wire options, so I had to resort to using a speaker wire.

Some of you might remember some questions I raised here on the board a few months ago, asking about flashing H1 bulbs and how to properly slow down an Aerodynic motor. You now know what it was for.
I obtained this bar from member Stampeed Valkyrie. Thanks to you, as I was looking forward for this project for quite some time now. I gave it my usual AeroDynic dome wet-sanding and polishing treatment. The bar was stripped and cleaned, but my expertise in this field in very limited compared to what other members here can achieve. (Eric and Sasha, that one’s for you ;) )Let’s just say I cleaned it the best I could. I also made one of my custom built switch box, especially for this bar. A basic FedSig SW400 would’ve done the trick, but where would’ve been the fun in that?

Last but not least, for the purist out there (myself included), this bar was modified without altering the original elements and pieces of the bar.

Here are pictures of the bar, the additional wiring, cam and switches and videos of the bar from the front cut off view, rear signal only, and full rotation. It is now pretty crowded in there, but living up to its reputation, this AeroDynic remains as inefficient and terrible as it normally should be for intersections and off-angle warning.

I hope you will appreciate it as much as I had fun completing this project!


Various views







Domes off

Additional contact strip and relays:
-Cluster on far left is for controlling the motor speed according to the full/rear warning position desired
-Bottom left is the additional contact strip to seperate motor speeds and front-rear lamp activation
-Brass plate under the idler gear holds the micro-switch that ''times'' the front cut-off option



Micro-switch holding plate and wooden cam-switch



Motor resistor to slow down speed while in front cut-off mode

Bundle of wires to separate front takedowns with flashing takedowns

Freshly wet-sanded and waxed domes with new NOS endcaps


...and the videos, of course!

Rear flashers only

Rear flashers + full rotation

Front view, full rotation + flashing takedowns

Front view in front cut-off mode. Notice the sweep on the fence, yet nothing to the front.

Rear warning only

Front and back, longer videos, darker surroundings.
Last edited:


Veteran Member
Thanks for the comments :)

The finished working bar is the tip of it, but lots of trial'n'errors happened before that. I'll try to get another video with all the options going at once.

Stampeed Valkyrie

Senior Member
Silver Supporter
There is much WIN in this post.
Great job.
It's twin is still awaiting restore but will be done soon.
Gotta get back from CA first.


Site Regular
Wow, that is over the top. Hats off to you. I would have love to have one of those on my patrol car back in the days I was a road dog.

Stampeed Valkyrie

Senior Member
Silver Supporter
So you don't regret selling it still ? ;)
Yep with Aerodynics I rarely part with them. This one turned out great.. so no regrets on my end.

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