LEDs for instrument cluster and VDO gages

After replacing dash bulbs every 3 years or so (as they're on with the DRLs) I switched to LEDs. I used white LEDs in keeping with the car's era, with

400ohm series resistors, if I remember correctly. Could probably go less than this as there isn't 12v at the cluster, in fact the digital clock backlight is much less - best to measure it first, then select the resistor value to get the right illumination. Because I wanted to keep things as OEM as possible, I made new LED replacement "bulbs" from burnt out ones by embedding the resistor in the mounting. Here's a pic: just have to watch you get the polarity right when you put them back in. The light isn't as dispersed, here's a pic of an LED over the tach and regular bulb over the speedo - next time I'd reduce the resistor to brighten the LED and diffuse its light somehow, perhaps by filing flat the LED dome.

Thanks, John. Great response!

One question. How can you determine the correct hookup in regard to the polarity?

Check this site. There may be others that sell these too. They also offer several different colors. Plug & Play for $11 pair.

Oops! Here is the site this time:

Thanks, Corrado. Much appreciated!!

Today I found what I think is a good bulb for this application for the VDO gauges. It is the Pilot LI-194W LED Indicator Lamp (clear) sold by Pep Boys at about $6.50 for a package of two. These are at least as bright as the incandescents, if not brighter, so only a single LED is needed in each VDO gauge to provide good illumination. Also, no resister is required, and with just a very small enlargement of the lampbulb hole in the back of each gauge they will fit very well.

These LEDs have bare solid (not stranded) leads that are about 1/2 inch long, and that end of the bulb would be external to the gauge case.

I'll do a follow-up post to discuss the electrical hookup once I get these LEDs installed.

You could test the circuit board for polarity with a multimeter, mark the

+ve, and make sure the LED's longer leg goes on the positive side - or, as I did... by the time you've trimmed the legs, fitted the series resistor and glued the assembly back into the old bulb holder, you've forgotten which way round the LED was ;-) in which case you plug it in and see, there's a 90% chance it'll be in the wrong way round, first time! Probability decreases somewhat on the second attempt.

The LEDS on

look good if you'renot into making your own. I'm not sure there's a suitable replacement forthe VW dash lights, but the LB74 series look closest - but not available inwhite.

Well, I found yet another LED bulb that looks promising. This one, a T1.5 instrument LED bulb, which is a # 74 LED installed in a twist-lock socket base, was unavailable locally so I ordered one unit from

at a cost of $1.79 each plus $5.00 for shipping. Hopefully it will fit the opening in the back of my VDO gauges. It sure appears to be the right size, judging from the drawing provided at that website. The bulb is claimed to have wide-angle illumination and is available in white, blue, green, red, and amber. It is a single, not multiple-clustered, LED.

When it gets here I'll give it a try and post the results in this thread.

Nice find,

Let us know if it fits. I'm surprised you didn't order a few as I'm sure the shipping is a flat rate! btw: Which generation of VW are you putting it in? and it's for the main cluster, right?

Another aspect people may be wondering about is whether the dimmer still works. Seems to be as functional as it was with the old bulbs, even though you may expect the LEDs to dim and then switch off completely at lower voltages.

My car is a 1988 VW (Rabbit) Cabriolet convertible. Right now I will be installing LEDs in my 3 VDO gauges located in the center console. Later I plan to put LEDs in the instrument cluster as well. Guess I'm a cheap skate for not ordering more LEDs, but I wanted to try one of the T1.5s out before buying more.

Yes, I'm wondering if the dimmer will still work too. We'll see.

I received the T1.5 LED yesterday. It fits the "twist-lock" holes in the VDO gauges perfectly. Unfortunately the electrical connection is not accessible from outside the VDO gauges. The T1.5 expects the electrical source to be inside the gauge, like it is on the circuit board of the instrument cluster (i.e., on the bulb end rather than the black "twist-lock" end). Hopefully Superbrightleds.com will have a "twist-lock" LED that will work with the VDOs. I sent them an email asking if they have them.

I could modify the T1.5 LEDs by soldering short leads to the positive and negative terminals of the T1.5. but it would be tricky feeding the leads to the exterior end of the bulb, and I might have to drill 2 small holes in the "twist-lock" in order to provide a path to the outside for the leads. Work I'd rather not do.

By the way, the T1.5 illumination capability is good.