Main Beam Warning Light Failure

[ianvfr750]

I've got a failed main beam warning light on my 1991 T25 Autosleeper - I got a replacement blue capless bulb from Brickwerks thinking this was the correct replacement bulb but now that I've stripped the dash out the bulb won't fit.
The existing bulb ( which is black i.e. blown) is not a capless bulb but a tiny bulb about a quarter of the size of a capless and has 2 long wire prongs.
Can anyone suggest a supplier for this bulb as I can't find one online or on the usual suppliers ( Brickwerks/Just Campers) websites.
Any assistance much appreciated.

[AngeloEvs]

Not familiar with the Brickworks replacement, it may require you to remove the plastic insert that the bulb fits into which is just a blue cap that can be removed. The bulb may be too bright without that cap.

An alternative would be to replace the original filament bulb with a 3mm 12v blue or white LED as it will fit into that cap and help to dim the brightness of the LED. I would look for a standard brightness type rather than superb right.

Hopefully, If the original miniature bulb is available someone will reply with a source.

My main beam is converted to an LED so I may have a couple of working filament type you need - will take a look and update later.

[ianvfr750]

Thanks AngeloEvs - I've decided to go the LED route as you suggested - spent most of yesterday looking for filament bulb but no luck - got LED on ebay in 2 minutes.
Thanks again.
Ian.

[AngeloEvs]

Forgot to mention that the LED is polarity sensitive, if it doesn't work first time, reverse it in the socket.

[RazorRiggott]

I've got a failed main beam warning light on my 1991 T25 Autosleeper - I got a replacement blue capless bulb from Brickwerks thinking this was the correct replacement bulb but now that I've stripped the dash out the bulb won't fit.
The existing bulb ( which is black i.e. blown) is not a capless bulb but a tiny bulb about a quarter of the size of a capless and has 2 long wire prongs.
Can anyone suggest a supplier for this bulb as I can't find one online or on the usual suppliers ( Brickwerks/Just Campers) websites.
Any assistance much appreciated.

I've got the same problem. The bulb seems to be fitted into the plastic unit with the bulb below. Can this unit be removed from the ribbon easily? Did you have to solder the led? Looks tricky!

[ianvfr750]

I've not tried to fit the LED yet.

I was expecting to just plug the LED into the housing ( the picture on Ebay showed an LED with 2 prongs just like the existing bulb ) but I didn't realise the LED came with a resistor attached to one leg which makes the LED prongs too long to fit into the black plastic housing.

I was intending to try and cut the leg and resolder the resistor up nearer the bulb but it looks very fiddly and I'm no expert with a soldering iron and even with the leg cut down I don't know if the thicker leg with the resistor fitted will fit into the existing housing.

If this doesn't work I'll be back on the forum to see how others managed to convert to LED.

[AngeloEvs]

Search for EBAY seller Spiratronics, he lists warm white 3mm 12v LEDs. In packs of 3. Send him a message and make sure the ones he sells do not have a resistor in the leg.

Regards modifying the dash to accept a standard 5mm or 3mm LED, if your dashboard retains the original membrane PCB then you will need to replace the resistor that is already there for the main beam bulb. The resistor is there to dim a standard filament bulb but its value of 100 ohms is far too low for an LED and the LED is most likely to fail. It is, with care, possible to replace the resistor with another that has a much higher value. The location of this resistor depends on which year dash you have fitted. I can give you details of what is involved to carry out the replacement but see if Spiratronics can supply the correct type of 3mm LED without a resistor in the leg.

Alternatively, I probably have some used main beam bulbs if that is of any help to you. You can have one at no charge but let me check that they work.

[RazorRiggott]

I've not tried to fit the LED yet.

I was expecting to just plug the LED into the housing ( the picture on Ebay showed an LED with 2 prongs just like the existing bulb ) but I didn't realise the LED came with a resistor attached to one leg which makes the LED prongs too long to fit into the black plastic housing.

I was intending to try and cut the leg and resolder the resistor up nearer the bulb but it looks very fiddly and I'm no expert with a soldering iron and even with the leg cut down I don't know if the thicker leg with the resistor fitted will fit into the existing housing.

If this doesn't work I'll be back on the forum to see how others managed to convert to LED.

I intend on tackling this at the weekend, so will let you know how I get on!

[RazorRiggott]

Search for EBAY seller Spiratronics, he lists warm white 3mm 12v LEDs. In packs of 3. Send him a message and make sure the ones he sells do not have a resistor in the leg.

Regards modifying the dash to accept a standard 5mm or 3mm LED, if your dashboard retains the original membrane PCB then you will need to replace the resistor that is already there for the main beam bulb. The resistor is there to dim a standard filament bulb but its value of 100 ohms is far too low for an LED and the LED is most likely to fail. It is, with care, possible to replace the resistor with another that has a much higher value. The location of this resistor depends on which year dash you have fitted. I can give you details of what is involved to carry out the replacement but see if Spiratronics can supply the correct type of 3mm LED without a resistor in the leg.

Alternatively, I probably have some used main beam bulbs if that is of any help to you. You can have one at no charge but let me check that they work.

Thanks for this, incredibly helpful. I've ordered the correct led and have a ribbon type circuit board, so would appreciate knowing how to change the resistor. My T25 is an 88 Autosleeper on an E plate.

That said, just replacing the bulb would be far easier and I'd be happy to pay for one if you do have a spare.

I also intended on replacing the 3 main dash illumination bulbs with lesds from Brikworks, though assume this may also have the same resistor issue?!

Cheers, Chris

[AngeloEvs]

The simple solution is a white 12V 3mm LED as this will fit into the blue cap and no other mod is needed. The Blue cap should reduce the intensity. Unfortunately, most LEDs today are of the superbright type but try to source the lowest value of brightness which is stated in units of mcd (millicandles) i.e 1000mcd, 3000mcd, 4500mcd.

To replace the 100ohm resistor fitted on the membrane pcb resistor in order to use a standard LED then try and source a 5mm Blue diffused standard brightness type. (the standard diffused standard brightness seem more difficult to get these days)

With the dash removed, remove the blue cap that covers the main beam filament bulb. It is just a push fit and can be pushed out even though it feels quite tight.

If you look at the picture below of the later dashboard (post 1986-7 which have the Buzzer of Doom), you can see a number of resistors to the right of the clock or Tacho housing, the top one (above the arrow marked 22ohm) is the 100ohm for the filament bulb and the one that needs to be replaced.

Measure it first with a multimeter to check that it is indeed 100ohms or therabouts.

Using small cutters, cut this resistor as close to the resistors body as possible. This will leave the leads that are crimped onto the membrane pcb available in order to fit the new resistor onto.

You can see that the new resistor stands a bit higher than the others.
The leads should be gently bent up and run a stanley blade over the leads to remove any tarnish and ensures you can ttin them easily and quickly.

Using a 15W or 18W soldering iron and good old fashioned 60/40 Tin and Lead solder (avoid Lead free solder - the melting point is higher and the joints not as good), gently tin the leads close to where you cut them. It only takes a second - no need to leave the soldering iron tip in contact with the leads for more than a second or so.

Since most LEDs are superbright I would fit a 1/8W 10K resistor, cut and bend the legs then tin them. Bring it into contact with the original leads and put some fresh solder onto the tip of the iron. It should only take a fraction of a second to solder each leg of the resistor.


LEDS are polarity sensitive, the longer leg is the positive, you can either trace the 100ohm resistor and see which part of the bulb socket it goes to and note that this is the positive or fit it and try and if it doesn't illuminate reverse it.

rear90v4 by Angelo Evans, on Flickr

[RazorRiggott]

Managed to source the correct resistor anda 2009mcd blue led that slots straight in. Thanks for your help with this. Your drawing helped a lot!

[RazorRiggott]

I've not tried to fit the LED yet.

I was expecting to just plug the LED into the housing ( the picture on Ebay showed an LED with 2 prongs just like the existing bulb ) but I didn't realise the LED came with a resistor attached to one leg which makes the LED prongs too long to fit into the black plastic housing.

I was intending to try and cut the leg and resolder the resistor up nearer the bulb but it looks very fiddly and I'm no expert with a soldering iron and even with the leg cut down I don't know if the thicker leg with the resistor fitted will fit into the existing housing.

If this doesn't work I'll be back on the forum to see how others managed to convert to LED.

Ian. I have a spare resistor (dead easy to solder as it's the one at the top) and a spare blue led that will slot straight in. Message me your address and I'd be happy to post to you

[ianvfr750]

Thanks for that RazorRiggott but yesterday I fitted the 3mm 12v LED suggested by AngeloEvs and it works perfectly with the existing blue filter cap - its a little brighter than the original but not so bright that it will be an issue.
Thanks to both of you for your help.

Ian.

[Florence the Komet]

Hi all, I’m attempting this as my main beam warning light isn’t working, but am out of my depth - can I ask for advice? My questions will demonstrate my ineptitude- I apologise and only hope that other newbies reading this will find this helpful too!

I have dismantled the dash cluster as per Haynes manual, and can now kind of get to the bulb holder, but am not sure how to remove the bulb:

What am I trying to do to get the existing bulb out? A: Remove the entire black casing from off the ribbon? B: Remove what looks like a black end piece from the bulb holder, then remove bulb? If so how - razor blade in the line you can just about make out (I envisage this ending badly for me and the van!)? C: Or does the bulb come out of the holder as is - if so how as there’s nothing to grab on to and I’m worried about the reportedly brittle PCB ribbon?

And if I do get it out, can anyone give me an idiot-proof answer to whether the 12v bulbs mentioned in the thread above (http://www.ebay.co.uk/itm/122833160253) will require a resistor for my dash (anologue clock, 1989 2.1dj) or go in as is?

Please do tell me if I should just carefully put it back together and take to automotive electrician before I break anything!

Thanks in advance. I will endeavour not to destroy this excellent vehicle...

1989 autohomes komet 2.1dj 5-speed manual


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[TONYT25T25]

I think you can remove the bulb as they are similar to other lighting fittings of this size, the problem is getting a good purchase on the bulb to remove it without damaging it, I had a similar problem with the handbrake warning lamp, but found out it was a dirty/bad contact on the unit holding it and not the bulb itself, I would have a good look at where it connects to the ribbon to see if can be removed without damaging either item and then check the contacts to see if they are clean, sometimes they do corrode and a clean with a bit of abrasive will tidy it up, but make sure the ignition is not on so that you do not cross any terminals when doing so.  To test the bulb itself when outside the unit I used a lower voltage battery and a couple of bits of wire to see if it would light up it doesn't shine so much but better than blowing it.