Emergency service lightbars/beacons on CUCV

[KallyLC]

I have a Federal Signal Twinsonic lightbar on my M1008, I only use it for a few events a year, so It's got magnets for feet and a connector so I can take it off. The previous owner installed it and wired it up, I just added the inline connector so it can be removed. There is a control box in the cab that switches the lightbar and siren on.

I'm not exactly sure how the last guy wired it up, but whenever I turn it on, it puts a considerable load on the alternators. If i run the headlights and the lightbar at the same time, it tends to make the belts on the alternator squeal, even if they're properly tensioned. I know this lightbar does draw quite a lot of power, but they did use them and other types of lightbar on CUCVs back in the day, so there must be a 'right' way to wire them up.

I don't know if it's an issue with my lightbar or an issue with the way things are wired on the truck, but it doesn't seem right. Has anyone else got a similar lightbar on their truck who could maybe advise?

 

[Barrman]

What ground (earth) source are you using since you made the system removable? Is it a 24 volt system or a 12 volt system? You have the radio antenna set up as well. Are you powering radios while you try the light bar?

 

[M813rc]

We used TwinSonics on our cars back in the mid-80s. If I recall correctly they drew 22amps, and we ran them on a 12volt 25amp fuzed circuit. This was for a bar with four bulbs total (two back-to-back each side on a rotating base, with mirrors in between). They were chain driven by a single motor.
There was also a less common version with a separate motor for each side.

While checking all your wiring, you might want to make sure the light bar motor, chain, and rotator posts are clean and well lubricated. The white grease used tends to harden up over time and can really make the motor work to turn the lights. Cleaning that up and using fresh grease makes a big difference on how well these older bars work. I have Federal Jetsonic and Jetstream light bars on my two M1009s.

Cheers

 

[KallyLC]

What ground (earth) source are you using since you made the system removable? Is it a 24 volt system or a 12 volt system? You have the radio antenna set up as well. Are you powering radios while you try the light bar?

The radio antennas aren't connected to anything, they are just decorative. The truck is still 24v, but the siren and lightbar just run from a 12v source.

There are three wires coming from the lightbar:
- a ground wire that runs to a sheet metal ground point just above to the parking brake pedal, inside the cab.
- one wire that runs to an aftermarket fuse block on the firewall, through a 10 amp fuse, and then to a factory junction block on the firewall that supplies constant 12v, even with the key off.
- another wire that runs into the siren control box in the cab, through a small 15 amp fuse.

The lightbar currently works as intended, it just makes the belts squeal. I don't know if that 10 amp fuse on the positive wire is maybe not helping things.

We used TwinSonics on our cars back in the mid-80s. If I recall correctly they drew 22amps, and we ran them on a 12volt 25amp fuzed circuit. This was for a bar with four bulbs total (two back-to-back each side on a rotating base, with mirrors in between). They were chain driven by a single motor.
There was also a less common version with a separate motor for each side.

While checking all your wiring, you might want to make sure the light bar motor, chain, and rotator posts are clean and well lubricated. The white grease used tends to harden up over time and can really make the motor work to turn the lights. Cleaning that up and using fresh grease makes a big difference on how well these older bars work. I have Federal Jetsonic and Jetstream light bars on my two M1009s.

Cheers

My Twinsonic has 8 lamps, four that are fixed facing forward/back, and two rotators with two lamps each, driven by a single motor and chain. It might demand a little bit more power than other types due to all the lamps.

When I bought the truck a few years ago I cleaned the inside of the lightbar and greased the chain, and it lives indoors out of the weather when not in use. I'm going to replace all of the bulbs, so I'll check the contacts while I'm there.

I'm growing more suspicious of the 10 amp fuse mine is running through, now you mention using 25 amp fuses for a bar with less lights.

 

[TechnoWeenie]

Not sure how I missed this thread.

Halogen lightbars draw a TON of power.

Assuming everything is 'normal'/original, each bulb is 60W (standard Halogen wattage for the day) or 30W (depending on color and options). Even the most basic Twinsonic has 2 bulbs per side + motor which are gonna be pulling ~4A. So, 60Wx2 (x2 sides) (240W)= 20A +4A = 24A on a GOOD day. Some are outfitted with 4 rotators instead of 2 so you're now up to 48A - others had 2 rotators and flashers. But you're looking at roughly 25A at the absolute lowest and 50A at highest - again, depending on configuration.

The Twinsonic, however, is a little too old for the CUCV - the only reason you'd see one is if it was switched over from a previous unit to save costs, which wasn't too uncommon back in the day, to be honest, so I'm sure quite a few units were using them.

Instead, I would suggest moving to something like a Jetsonic. It's a Jetstream with siren speaker attached, and was EXTREMELY popular in the 80s. You can retrofit the halogen bulbs with LEDs which will keep the old rotator look while keeping the amperage drawn to a bare minimum. https://code3garage.com/equipment/federal-signal-jetsonic-jetstream-jetstrobe/

The Jet series definitely fits better on an early to mid 80's car. The Twinsonic was really a bar for the 70's.

The Aerodynic would also be a good alternative - as would the Streethawk or Edge 9000.

 

[M813rc]

That first picture looks very familiar, it is one of my trucks!

I still have that 1009 with the Jetsonic, and my other M1009 has a Jetstream (same bar but has another rotator in place of the siren). Both are set up with straight amber lenses for legal running on the roads here. Both are used as "Tail-end Charlie" when we move the big trucks to events.

Techno, y'all must have been more advanced than around here, even large cities like Austin were running some TwinSonics on their cars up until about 1989.
By 1987 the Whelen Edge strobe lights were on about two thirds of the cars, and all the old mechanical/incandescent lightbars were gone by 1990. It takes a while and a lot of $$ to switch out the lighting on 400+ cars.
Those Whelen bars were not fantastic, they were pretty anemic in bright sunshine (which is most of the year in Texas) and had a high failure rate of individual components. All had been replaced with Code-3 MX-7000 by the mid-90s, those were fantastic lights.
The Jetsonic/Jetstream would have been a much better interim choice than those Whelens. They had better visibility, were more reliable, and more easily maintained; I'd hazard a guess they would have been a lot cheaper to operate overall.

Cheers

 

[KallyLC]

Not sure how I missed this thread.

Halogen lightbars draw a TON of power.

Assuming everything is 'normal'/original, each bulb is 60W (standard Halogen wattage for the day) or 30W (depending on color and options). Even the most basic Twinsonic has 2 bulbs per side + motor which are gonna be pulling ~4A. So, 60Wx2 (x2 sides) (240W)= 20A +4A = 24A on a GOOD day. Some are outfitted with 4 rotators instead of 2 so you're now up to 48A - others had 2 rotators and flashers. But you're looking at roughly 25A at the absolute lowest and 50A at highest - again, depending on configuration.

The Twinsonic, however, is a little too old for the CUCV - the only reason you'd see one is if it was switched over from a previous unit to save costs, which wasn't too uncommon back in the day, to be honest, so I'm sure quite a few units were using them.

Instead, I would suggest moving to something like a Jetsonic. It's a Jetstream with siren speaker attached, and was EXTREMELY popular in the 80s. You can retrofit the halogen bulbs with LEDs which will keep the old rotator look while keeping the amperage drawn to a bare minimum. https://code3garage.com/equipment/federal-signal-jetsonic-jetstream-jetstrobe/

The Jet series definitely fits better on an early to mid 80's car. The Twinsonic was really a bar for the 70's.

The Aerodynic would also be a good alternative - as would the Streethawk or Edge 9000.

Thanks for the input, I wasn't aware untill I really dug into it just how much power the Twinsonic demanded, so it does explain why it's putting such a load on the system. My bulbs currently are a mixture of wattages, because they're apparently just whichever bulbs the previous owner could make fit. But I have a full set of the correct bulbs ready to go in it once I find the time.

The combined wattage of all the correct bulbs is actually slightly higher than what it is with the current bulb setup, but at least it'll have the right bulbs.

I have a lot of pictures of Air Force CUCVs with Jetsonics and Aerodynics, I particuarily like the Aerodynic. However, my Twinsonic came free with the truck, I already have it, and to replace it would be a ton of money for the sake of a couple of events a year. So, I'll work with what I've got for now.


Besides, the Air Force did have Twinsonics fitted to CUCVs at a base here in the UK at least up untill 1993, which is when this was taken. Granted, it's not on a Security Police vehicle, but the fact they were in use and fitted to CUCVs at all are the grains of truth I need.

Funny story, a guy I know used to have an M1009 up untill a few years ago. I showed him the video that screenshot is from, and it turns out that's his truck while it was still in service. The numbers on the plates match the numbers stencilled under the hood