High Beam Indicator problem

[Spacehopper]

I've got a 1990 square bumpered t25, and i think the dash is slightly different to the older ones in that there is a blue filter built into the high beam indicator housing.
The high beam light stopped working, so i picked up a 12v miniature filament lamp from maplin thinking it would do.
The wire end legs are a bit flakey compared to the lamp i took out but i got it in ok - but it doesnt work.
I stuck the old one back in and found out it actually does glow everso slightly.

I don't really know where to go now.
It definitely is a 12v miniature bulb thats required isnt it? I wondered whether maybe the later versions of the lamp needed for my type of dash are actually brought down to a lower voltage or something? I wondered if there just isnt enough power to light the 12v lamp i got. Maybe the thing thats blown is even an LED (doubt it cos its silvered inside)
All other leds are working fine, and the switches etc to operate high low beam all work fine too.

Has anyone else ever had anything like a drop in power to a single warning lamp? Should i start buying different voltage lamps?? Am i missing something?

[R0B]

http://www.brickwerks.co.uk/shop?page=s ... =main+beam" onclick="window.open(this.href);return false;

[Oldiebut goodie]

The obvious thing to do is check what voltage you actually have at the bulb connector. Leds are plastic encapsulated, bulbs are glass. The fact that you get a slight glow is possibly indicating a dodgy earth.( meaning you are only getting a low voltage passing through the bulb)

[Spacehopper]

http://www.brickwerks.co.uk/shop?page=s ... =main+beam

Thanks i saw this, but its not the type of bulb i have. I think this is from the older dash type that doesn't have the blue filter built in.

Re the dodgy earth, yes this sounds likely. The lamp holder is directly attached to the flexible pcb-ish circuit board, I'm not sure where the earth could be dodgy.Back at the chocolate block connector? I guess one of the pins is the live feed to the lamp, would they all share the same earth? I'm not great with electrics, any clue would be really appreciated.

E D I T: ie any pointers re what to wiggle or get some electrical contact cleaner into

[Oldiebut goodie]

I would get my multimeter out if I were you - a cheapo £5 one will be handy for all sorts of checking on your van. Two ways of checking it - check the actual voltage across the two bulb contacts and compare it to the voltage between the positive contact and a different clean earth on the bodywork (which should be very close to your battery voltage) - a large difference would indicate that there is an earth problem, or check the resistance between the earth side of the bulb contact and a clean metal point on the bodywork - which should be very close to zero - high resistance would indicate an earth problem.

[Spacehopper]

Excellent, thanks that's just the pointer i needed thanks

[CovKid]

You can also fit a blue LED (with correct resistor) in to the blue filter cap or dip a blue LED in black paint. Blue LED on its own is just too bright. When the T25 was built, blue LEDs didn't exist - hence the small filament bulb. At that time LEDs were mostly yellow, orange and green.