VW Bosch Horn HO/FDG Year Identification Help

[56vw]

Hi Guys,
Found this VW stamped Bosch Horn with screw terminals in my shed and wanting to know if it is the right one for my Oval. Tried searching but can not make sense of the numbers. Many thanks Cheers.

[virtanen]

Bosch should has a tiny date stamp, here 12J

_________________
Mika
Split beetle restoration panels
Oval beetle restoration panels
New projects

[finster]

think you might need an HO/FDF but not sure when they changed to FDG. is there anything stamped into the terminal block?
_________________
"we're here on Earth to fart around" kurt vonnegut

nothing lasts, nothing is finished, and nothing is perfect...

[56vw]

Thanks Guys.
Searched the rim for a date stamp but nothing found.

6/12 stamped on the terminal block.

Opened it up. Cleaned the points with sand paper. Put it back together and added 6v power. Nothing until I tightened up the adjustment screw a couple of turns on the back, and wow, what a great sounding VW horn. Deep and really loud.






Bottom pic is another VW Bosch Horn the same as mine but with 6/13 stamped on the terminal block.

What do these numbers mean?

[tasb]

The 6/12 won't be a date stamp since at that time Bosch used a letter number combination for date stamps. Beyond that not sure other than maybe just indicating voltage options. don't apply 24 volts to it without a suit of armor1
_________________
Roads Scholar &
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

[Frederik]

6/12 = first number is voltage (6 volt) second is "version". For example it could be different Hz or other variation for the same type (HO/FDG) of horns. It is not as often comfused a 6V/12V universal use.

I can check, but I think I have the specified difference /12 and /13 and if I remember correct they are set to different Hz.

[tasb]

Makes complete sense, different Hz for different models or even automobile makers. Once the horn is off the vehicle whose to say where it came from.
_________________
Roads Scholar &
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

[Rome]

Just guessing, if the HO stands for the German word hoch, meaning high? In case of use as dual horns such as Karmann Ghia, to differentiate with the lower tone horn possibly designated as TI (German for low = tief, pronounced teef).

[finster]

I think the HO stands for Horn as even in two-tone set-ups I've never seen a different reference.
https://www.thesamba.com/vw/archives/lit/55bosch_hints/1955bosch_hints.pdf
_________________
"we're here on Earth to fart around" kurt vonnegut

nothing lasts, nothing is finished, and nothing is perfect...

[Rome]

That makes sense; thanks for the reference, finster.

[Frederik]

In the "old" Bosch part numbers the first 1 or 2 letters always is the main group. H or HO = hörner but other examples are ZV = zundverteiler, ZS = Zundspulen, LE= Leuchten..

The 2nd group of letters is the sub group. First number(s) after the sub group is a group number (many parts that are simular could have the same group number, in this case all same type of HO (horns) of sub group FDG group number 6 = 6V). Second number(s) after a "/" or "L" is a part number and specified the version/ difference (with horns it could be tone, chrome/ painted, and other small details)


The HO/FDG horn is a later horn. An oval should have a HO/FDF 6/47.

HO/FDF was "normal" horns for cars, tractors and motorcycles. They ara basicly the same as the HO/FSA "loud horns" but has a smaller membrane.

The universal models (for 6 Volt) was: HO/FDF 6/..

3: black house, without grille, low frequensy, tone D
4: -"-, -"-, mid-high frequensy, tone F sharp
Could also be used together for two tone, tuned in third. If used alone the low tone was usually used.

Versions with amplifed signal (6 Volt): HO/FDF 6/
45: black house, black grille, low tone, tone D
46: -"-, -"-, mid-high frequensy, tone F sharp.
Could also be used together for two tone, tuned in third. If used alone the low tone was usually used.
47: special version made for VW, other same as /45
56: same as /45 but chrome grille
57: same as /46 but chrome grille

[56vw]

Many thanks Guys for your knowledge and the interesting information.

I gave the horn a light wire brush and then a shot of enamel paint.
What a difference.

Before

After

Thinking I might mount it up outside as a second twin horn with a custom bracket on the bumper iron as depicted in the period Bosch Booklet.

I understand not period correct, but just too cool to hide away under the mudguard unseen.

With this new clean up and coat of paint, it should last another 60+ years on the Oval.
👍

[Rome]

30 years ago I bought a December 1952-built Zwitter split-window Beetle quite cheaply. I was buying numerous parts from a Connecticut VW enthusiast who offered me two larger Bosch paired horns, thinking they were from "an old Mercedes". I contracted a colleague to do some welding on the body at home using his 110 V Snap-On MIG welder, including attaching a horn bracket in the right front fenderwell to match the position of the stock driver's side one. Those horns were very loud with the car's 12 V. Seeing Frederik's details about the horn codes and your excellent results with the repainting, I wish I had made a few detailed photos of the horns at the time to also record the horn codes. I sold the car in 2003.

[Frederik]