[T3] Emergency Flasher Wiring

[jadney at vwtype3.org]

Sean,

Thanks for the explanations. Now I understand what the other terminals got 
used for in earlier Beetles and Buses with just 2 filaments in the rear. I've 
always thought it weird how some makers went to such extreme efforts to 
avoid adding another filament. Thinking about  I, it strikes me that it's 
possible that someone invented the 2 filament bulb, just to solve this 
problem. I wonder when that happened.

I don't own a copy of the Big Blue Bentley; maybe that's what I need next 
Christmas. I DO own two different copies of the official VW Dealer Workshop 
E (electrical) manuals. One (dated '69) is a single volume, while the later one 
is in two volumes. Both cover Types 1, 2, and 3, and the later one probably 
adds in Type 4s. Both show the same '66 Type 3 wiring diagram posted on 
the Samba, with just 4 teminals on the TS relay. This is what all the US VW 
dealers had, back in the day.  If the Big Blue Bentley has a better diagram, I 
wonder where Bentley got it.  

The 4 terminal relay is also the only one that shows up in all my aftermarket 
manuals. It's clear that this is wrong, but you'd think that some of them would 
have gotten it right.

Why doesn't the correct diagram show up in any of the other sources I have?

Kudos for the test setup you built. Nicely done.

Jim

On 6 Mar 2026 at 15:43, Sean Bartnik wrote:

> > If the '66-7 relays were all 9-terminal, how do you explain the 4-terminal 
> > relay shown in the '66-7 wiring diagram?
> 
> I can´t explain it. Just took a look at the diagrams on the Samba. The source that shows a 4-pin relay in a ´67 looks like it came out of a later printing of the Bentley so maybe it´s just mislabeled? If you look at the color diagram that came out of the Big Blue Bentley it shows the 9-pin.
> 
> > Were they simply not showing 5 
> > terminals not used. Yes, I also thought those years used a very complicated 
> > multiple pin relay, but it seems odd for VW to buy hundreds of thousands of 
> > relays with features they didn't need.
> 
> Perhaps because it was used across the model range it made financial sense to VW to just have one flasher relay across all models rather than one design for Beetles/Buses and a separate one for Type 3. Just speculating of course.
> 
> > 
> > Now that I'm thinking about it, dual filament just puts two functions into one 
> > package. It doesn't change what's required from the relay. Don't all years 
> > have 3 functions with separate filaments dedicated to each function? So I'm 
> > not understanding what needed to change in the wiring at the flasher relay.
> 
> I think I got a little ahead of my proofreading in my post. Yes of course you´re correct that all Type 3s of all years have 3 separate filaments dedicated to each function. This is why the 54 circuit is not used on Type 3s.
> 
> It was the Beetles and Buses of the era that had only two filaments dedicated to all 3 functions. One filament for taillight, and the same filament in the same bulb to handle both brake light and turn signal. So the wiring for the brake light switch runs through the flasher relay via the 54/54f circuit. When neither the turn signals nor the flashers are engaged, the 54 circuit is just a pass-through for the brake lights. But when the turn signal or hazards are engaged, the relay cuts out the brake light signal and instead puts the pulsing signal to the bulb on the appropriate side (or both sides for flashers).
> 
> Later models of both Beetles and Buses did get 3 separate filaments for the 3 separate functions.
> 
> > 
> > Nice video. At first, I guessed that your 4 bulbs represented the 4 TS bulbs 
> > at the 4 corners of the car, but when you tested brake lights, it seemed like 
> > all 4 bulbs lit up.
> 
> They did :-D 
> This was a side effect of how I wired the board. I could have complicated the wiring a bit more and wired it so only the two bulbs representing "rear" lit up when I closed the brake light switch but since the main purpose was merely to test the 54 circuit the way I wired it serves that purpose and was simpler to make.
> 
> 
> > Maybe I'm confused and none of the filaments in your setup 
> > are for brake lights. It certainly looks like you must have incorporated diodes 
> > to put your 4 filaments to multiple uses (flasher, taillight, brake.) What am I 
> > missing? Are two of those bulbs dual filament? (I can only make out 2 wires 
> > to each.) What am I missing?
> 
> No diodes, just 4 single-filament bulbs wired as they would be in the car (with exception noted above) and with toggle switches doing the work that the ignition, brake light, turn signal, and hazard switches do as in the car. Basically just copied the wiring diagram onto a board.
> 
> -Sean
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-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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