dash display bulbs ????

[malcolm2]

While waiting on my RUST CONVERTER to convert, I started pulling the dash.

I decided to destroy the little pins that hold the vent controls. Seems like what most folks do.

Then I got the gauges out and started checking bulbs. The 914 BBS guys have taught me that the G light must remain incandescent. On the 914 the bulb actually helps start the charging process. LED will not pull enough amps, or something like that.

I have a box of LED bulbs to change. I changed the back lighting, the Bright and Parking indicators. But that is it.

Anyone go with all LED?
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My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[babysnakes]

I have not, but the general consensus is the G light remains incandescent. LED for the rest.

[Hikelite]

I think the real problem with an LED is it won't dim correctly.

I can't find it, but I was just reading a post Telford made saying you can put an resistor in series with the LED to provide the load that the alternator needs. He didn't recommend it per se, but said it could be done.

If you have a T1 motor with an alternator, and only use that light to indicate the presence of the fan belt, then you could go all LED in theory.
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~Kevin

My 1968 Campmobile

[kreemoweet]

[malcolm2]

[telford dorr]

A resistor paralleled with an LED dash lamp will allow enough current to flow to the alternator to start properly. The stock bulb (N17 751 2) is a 12 volt, 1.2 watt lamp. This means that it has an operating resistance of 120 ohms. I'd use a 100 ohm, 2 watt resistor (Frys, Mouser, Digikey, etc.) paralleled with the LED (a little extra current won't hurt).

Yes, LEDs are dimmable, but you can't do it successfully by adding resistance. You do it by using pulse width modulation (turning the LED on and off electronically really fast such that you can't see the flicker). You can buy dimmer controls using this technique on Amazon.

Here's a link to my dash light LED conversion.
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'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[mikedjames]

The other thing the G light does is come on when the battery positive or negative falls off and the alternator or generator is producing a too-high voltage.

For that you need a filament bulb, as the current flows the other way through the bulb to the usual generator/alternator not outputting enough voltage scenario.

The LED would stay off while any electronics in your bus is being fried.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[Wildthings]

How long is your Charge Light ever on? A few seconds every time you drive you rig. There aren't any great savings on changing it out and for the vast majority of time the amount and color of the light isn't going to make any difference to the appearance of your dash as the light just isn't on enough to matter.