Digital unit for A/C led malfunction

[johne]

There are 4 bulbs illuminating the climate unit. The outer two bulbs illuminate the switches, have a light green coloured body and are rated at 2 watts. The inner two bulbs backlight one of the lcd screens each. They have a green body and are rated at 0.9 watts.

All bulbs are clear, the colour comes from filters inside the unit.

The screen bulbs, that's the inner two, could be replaced by red led units but you may well end up with uneven illumination across the displays.
The switch bulbs, that's the outer two, could also be replaced by led units but they'd have to be white ones since although most switches are illuminated red, the "A/C" switch is illuminated white.

If you do use led ones you'll have to use trial and error to get them in the right way round as they will be polarity sensitive.

If the display unit does turn out to be faulty, it's not hard to swap the displays over from another unit. Even easier is swapping the whole front panel over as it's on a multiway plug.

John

[A80Avant]

thanks for the answers John. So basically im looking for 0.9W and 1.2W bulbs for this. I have seen leds of 1.2 and 2W being sold online but ill go with the intensity that is required. Are these bulbs having a specific name that are easily to be googled?

[johne]

509T or T5 cap.

This is the item number for red leds on ebay at the moment. Haven't used these or this seller myself.

230357722920

When you see 1.2 watt or 2 watt leds for sale they don't mean that the leds are 1.2 or 2 watts, they mean that they are replacements for 1.2 or 2 watt regular bulbs. Leds only use a fraction of the power regular bulbs do. Leds do vary in power/brightness but sellers rarely quantify that. The downside of leds is that they are polarity sensitive which in practice means being able to power up whatever you've fitted them in to check they're in the right way round and their light is much more directional giving you a bright spot straight ahead and less light all round.

John

[A80Avant]

http://www.audi-sport.net/vb/a4-s4-forum-b5-chassis/75778-instrument-cluster-bulbs-change-pics.html

according to this guy here the green bulbs are rated at 2W.

i found these: 1.2W

http://cgi.ebay.co.uk/BOX-10-CAPLESS...item20b0482c7d

and cheaper
http://cgi.ebay.co.uk/286t-12v-1-2w-...item35ac97a3a1

[A80Avant]

and this guy for leds

http://cgi.ebay.co.uk/AUDI-SPEEDO-DI...item3f01856eeb

if you change them with white leds, that is what i fear that it might cause problems because white in leds is sometime blueish... so if i go to red it might be too intence. Although i have used red leds for the cigarrete lighter and it looks ok.

[johne]

and this guy for leds

http://cgi.ebay.co.uk/AUDI-SPEEDO-DI...item3f01856eeb

if you change them with white leds, that is what i fear that it might cause problems because white in leds is sometime blueish... so if i go to red it might be too intence. Although i have used red leds for the cigarrete lighter and it looks ok.

In the CCU I think white leds will be fine for the switch illumination as most are red and there isn't much to see on the A/C button and as the light is "piped" to the buttons the directional nature of leds won't matter. For the display I fear that if you use red leds you'll end up with uneven lighting as the bulb is behind the centre of each display with little diffusion.

John

[A80Avant]

i see what you mean. Well i made a purchase of few options and will report back once i change them to see the differences. I also got the pack of the normal ones. Although audi has the orange ones for the dash and some black ones for the centre, i think that using black everywhere should be ok. We'll see!

[siV6Qcoupe]

I did consider using the LED CC unit facia from the "D" suffix unit (97/98 A4) that uses many of the micro surface mount LEDs. Unfortunately the connector plugs are different where the ribbon cables attach also the pin numbers are different it seems. I'm sure it could be made to work if the function of each pin was known and compared to the '96 year units and an adapter cable made.

[A80Avant]

all led's and bulbs arrived yesterday. I took the AC unit off and saw the 0.9W and 2W bulbs. I replaced the 0.9W bulb which was burnt as well as the one next to it with 2 white LEDs. unfortunatelly the LEDs do now have a wattage output on them, so i dont know what their output is.

Is the Wattage related to the amount of heat they may produce, and therefore we should stick to the specification ? If replacing with leds, i suppose heat shouldnt be a problem, right?

I tried to see if a white led would be better on the 2W bulbs, but it wasn't as strong as expected, so i kept the original.

Im going to try and see if the use of them is better on the main dash as well.

Finally, how much is the wattage on the orange bulbs? I got a box of black ones which are 1.2W. Since the dash has a potentiometer modifier of the light intencity, does that mean that the 1.2W can be used as well and modified by the light intencity potentiometer?

[S2central.net]

Can I make a mad suggestion and just renew the dead bulbs with same type filament bulb items instead of faffing around with LEDs. I don't see any upside with using them here - just costing you time & hassle for no benefit really.

[Audi-Porsche Avant RS2]

Orange Socket Osram bulbs are 1.1 Watt, on mine S2, RS2 and Cabrio I have all the rights bulbs and the nightstyle is good for me.
Alessio

[johne]

Can I make a mad suggestion and just renew the dead bulbs with same type filament bulb items instead of faffing around with LEDs. I don't see any upside with using them here - just costing you time & hassle for no benefit really.

Just for completeness, I bought a couple of LEDs and tried them in my CCU. They are absolutely useless, even worse than I expected so as far as illuminating a CCU is concerned, stick to the regular bulbs for illumination it was obviously designed for.

John

[S2central.net]

I rest my case

[A80Avant]

Yes paul, i understood that, you are clearly against LEDs.

i used 2 white for the A/C for the middle screens and they work fine. I agree they cannot replace the 2W side ones as they are too dim.

I havent used the other leds for the dash, because i consider them a big faf to test them all the time, but i did change all orange bulbs with the 1.2W black ones i found and they work fine. Personally i dont like the solution Audi came with, using orange caps to produce the backround lighting on the dash, and if leds were more robust, wider in illumination etc i would definitelly change them

[Jamo]

Where's the best place to buy these bulbs? can't find the 0.9W ones on the weblinks above