Adventures in replacing a missing blinker indicator light

[indianpeaksjoe]

Follow along as I solve the mystery of the missing in speedometer flasher indicator light.

So on my 66 it was converted to 12v prior to me. The PO did great at everything I should have assumed something as simple as a missing bulb and bulb holder would not have prevented them from getting this working if it was that easy.

There was an empty tab on the flasher relay that was just BEGGING for me to hook a light up to and be done. But accepting that I am new to this I decided to try a few things out before blowing a fuse or causing a fire.

First, I tried a test light from the negative to tab, it all worked, the same with the spot in the speedo to the relay tab.

Next I tred with a bulb from negative to the relay.

And then I plugged it in, it lit up dimly and the blinkers worked poorly.

So then I broke out the voltmeter and found of the blinker bulb is center negative, so I need to switch that, not the positive from the existing relay. I confirmed this with a spare 2n4403 NPN transistor I had. This is not rated for this load, but it confirmed it worked. Of course a quick google of the samba showed me there is a part from Wolfsburg West. Which would have saved me some time, but what would the fun be in that?

Cheers,
-Joe
_________________
Adventures in owning a 66 beetle

[indianpeaksjoe]

Join me on part 2 as I fall victim to impatience and try to use a generic relay as I wait for the part to come in.

I bought a generic 4 pin relay from my local Oreilly. I figured I could just wire this in for the heck of it.

Everything worked great on the bench.

In the car, it did not

More pics of this part here: https://robonza.com/beetle/index.php/2023/12/03/re...-and-pain/

I should probably have just waited for the right relay But it was still fun, and isn't that the point?

Cheers,
-Joe
_________________
Adventures in owning a 66 beetle

[MrGoodtunes]

Mine works in my kitcar exactly as it did on the bench. Short mockup video, here:
https://youtu.be/PPGPlrlwGnk

More info, here:
https://www.thesamba.com/vw/forum/viewtopic.php?p=9781514&highlight=#9781514

[indianpeaksjoe]

Thanks Mr Good Tunes, that is helpful!

Also, I kind of need to know what sort of radio you've got in your buggy with a name like that !

Cheers,
-Joe
_________________
Adventures in owning a 66 beetle

[MrGoodtunes]

[indianpeaksjoe]

Very nice! that is a bit fancier than my USB speaker in the back seat.

-Joe
_________________
Adventures in owning a 66 beetle

[ashman40]

Do you mind if I ask a few questions?

The thread name suggests your turn signals work fine it is just you do not have a dash indicator lamp for your turn signals and you are trying to get one working. Is this what you are trying to do?

Are you trying to get the indicator lamp in the center bottom position on your speedometer to act as your turn indicator lamp? Or do you have a separate bulb in some other location you are trying to use? Is it the 2W stock bulb your pics show? Or are you planning to use some other bulb as the turn indicator lamp?

Do your OIL and GEN indicator lamps in the speedometer work normally? Do they turn ON with the ignition switch before you start the engine and then turn OFF once the engine is running?
For this to work properly the bottom most terminal on the speedometer should have a 12v+ ignition switched wire connected to it. This provides a shared 12v to the three bottom indicator lamps. Each of the wires coming off the three bulb holders runs to a ground which turns the respective indicator bulb ON.

Do you have LED lamps for turn signals in each corner? Or are you running the normal 25W incandescent lamps in each corner?

I would suggest that you get the turn signals working as expected with the turn indicator lamp in the dash removed. The (EP35) flasher relay output terminal (49a or L) connects to the INPUT to the turn signal switch. The flasher relay INPUT (49 or +) connects to an ignition switched 12v power source. The Ground terminal (31 or -) connects to a good ground point. In this configuration the 49a OUTPUT is just waiting for the turn signal switch to open a path to the corner lamps where the flasher relay may power the corner lamps. Once the path is opened thru the turn signal switch the flasher relay will pulse the 12v OUTPUT.

Once you get this working, install the 12v, 2W turn indicator lamp into the speedometer. This lamp sits between the 12v+ wire connected to the bottom of the speedometer and the 49a (L) terminal of the flasher relay. Yes, the indicator lamp sits between an ignition switched 12v+ power source and a pulsing 12v+ power source!
One of the key requirements for this odd circuit to work is that the corner turn indicator lamps need to have a much higher wattage rating than the 2W dash indicator lamp. Each corner lamp should be about 10x the dash lamp wattage. Stock corner 12v bulbs were 21W to 25W each.


Report back if your corner lamps work properly with the dash indicator lamp removed. And what happens when you install the dash indicator lamp?
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[indianpeaksjoe]

Hey Ashman ! Thanks for all the info.

To avoid confusion I will define the following two terms. I am not implying you do not know the terms, rather I do not know the appropriate nomenclature.

- Turn signals are external the lights at the four corners of the car.
- Indicator is the 2W incandescent bulb in the bottom center of the speedometer.

My turn signals all work fine, they do indeed blink when they should. They are LED lights in the turn signals. Which to your point about the current draw may be my problem.

All of my other lights in the speed work, the gen, oil and highbeam all work as planned.

When I add the 2W indicator to the dash I get a very dimly lit bulb that blinks so dim it can only be seen at night and even then, barely.

Thanks for the help!

Cheers,
-Joe
_________________
Adventures in owning a 66 beetle

[KTPhil]

I have similar behavior with LEDs, and will be changing back the indicator bulbs (I have a Type 3) next time I'm in there.

[ashman40]

[indianpeaksjoe]

I finally solved this... in a way that you may say is overly complex.

I used an Arduino, Adafruit current sensor and relay to monitor the current of the wire from the fuse box to the relay, if it goes up above 100mA then the relay triggers and the bulb goes on.

Wrong solution, rube goldberg? I don't know, but it works

Full write up here: https://robonza.com/beetle/index.php/2024/03/24/fixing-the-indicator-light-in-a-66-beetle/

Video of it working

Link


Have an awesome weekend.

-Joe
_________________
Adventures in owning a 66 beetle

[EVfun]

[indianpeaksjoe]

I swear I tried that, and once the dash bulb illuminated it caused the blinkers to go wonky. I'll try it again when this set up stops working

Have a good one!
-Joe
_________________
Adventures in owning a 66 beetle

[ashman40]