Help - Main beam warning light -FIXED UPDATE-

Don't think the main beam warning light in the dash has ever worked in the 18+ months I've owned the Cabriolet. Using it mainly in the summer months when it goes dark at 11pm its not been a major problem. The last MOT didn't pick up on it which was nice. However wanting everything to work properly :roll:  and driving around the NEC and M40 on the way home from the Classic Car show dazzling everyone I thought I would try and fix it.

After pulling the dash apart to get the instruments out, pin 7 blue and white wire on the multiplug to the instruments (as per Haynes and Autodata books) is +12v when the main beam is on and 0v when off so it looks like all that is working OK and the fault is with the instruments.  :cry:

The blue plastic membrane is ok with no burns or rips, looks like its never been touched before.

The warning light is blue unlike the yellow LED used on MK1 tin tops, I seem to remember reading that when the MK11 came out VW used an ordinary filament bulb behind a blue plastic cover as blue LEDs weren't availble so perhaps its the same on a '87 Cabrio and the bulb as blown :dontknow: There doesn't appear to be an easy way to change if that is the case  

Has anyone dismantled an instrument cluster and can give me any clues on what to watch out for??? It all looks very delicate with lots of clips/screws/nuts and bolts.

Any suggestions gratefully recieved

you can get any colour LED from maplins now, if you take the warning lamp part of the dash pod out (requires a fair bit of disassembly) the bulbs simply pull out like the ones in the ciggy lighter etc and they can be replaced as they just push in with two prong feet exactly the same way, i have some from an old dash i took to bits :wink:

yellow, red, and green ones i think.

Besides the dazzling issue dont worry about MOT time as a main beam warning light is NOT part of the test

Are you sure about it not being required for the MOT :dontknow: Thought mainbeam and foglights required a tell-tale in dash?

Bert we need your expert assistance  

Going to do a bit more prodding with multimeter and then decide wether to pull instruments apart.

Only trying to help………if you dont trust my answer  :dontknow:


it wasnt missed on your last mot AS YOU DONT NEED IT!!

Foglight requires a tell-tale but main beam doesn't.

No not questioning you TotR just very surprised, you learn something new everyday.

Doh, might put dash back together before I mess up something else, but then again whilst I have it in bits…..

No worries, you only learn stuff from experience………and about 10 years ago i had the same thing on my Lhasa GTI, its how i found out

the fact people flash you all the time if you dazzle them is warning lamp enough

You could always solder directly to the board .

Taking them apart is always a risk though so why not retro fit a warning lamp ?
Like the Lucas type fitted to Leyland cars etc .

UPDATE……..

Decided to pull cluster apart;

1st remove cluster from car, on a MK1 this involves removing half of the interior first…



To dismantle the cluster I removed the 8 screws (two not shown in pic to far right) and the lights that hold the blue circuit board down, highlighted in red….



This then allowed me to gently lift out the 3 main components (rev counter, LEDs/fuel gauge and speedo) as one held together with the blue circuit film from the cluster housing. Then when turned over I removed the black plastic LED 'shield' to reveal my problem. As suspected when built there were no blue LEDs so VW used a clear LED/filament bulb that had blown and a blue plastic mask;





Off to Maplins to get a blue LED, unfortunately they only had chav type bright blue LEDs, I got a clear one and this other shown with the original blown white LED style filament bulb. They were 3mm so could be used under the blue plastic mask so not a big problem. Insert the right way, short leg or flat side = -ve connection;



Put everything back together and test. Is brighter than the other LEDs but not as bright as camera makes out;



Job done and I now know a little bit more about MK1s!

well done mate i need to do the same cause mines broken too

been busy, well done.

Think I would have backed off when I found out it wasnt required.

If I'd known at the very start yes, but only found out when I'd already extracated the instrument cluster from the bowels of the dash.

If I was to do it again I would have used one of these lower 1.5cd output LEDs;
http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=35733&doy=31m12#spec

instead of the brighter3.2 cd type that I did use.

Just found that my MK2 conversion clocks high beam has packed in but it's an Led ? So thanks for the tips on replacement Early-1800

Do LED's blow ?

leds dont blow unless you over power one. should last longer than the car.

no gas to blow

thats bright now id like to see bright red and green to match now

Early-1800 said

If I was to do it again I would have used one of these lower 1.5cd output LEDs;
http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=35733&doy=31m12#spec

instead of the brighter3.2 cd type that I did use.

Just ordered some from Maplins

Thanks for the tip!