Rear fog tell tale light

[Matt&JoyBongling]

Hi,

out Bongo failed its MOT as the tell tale light for the rear fog light wasn't working. I've no idea when it stopped - it may not have been working for some time and I really can't remember if it ever came on - I habitually turn it off as soon as the conditions clear or I park.

The rear fog light works when the switch is activated. The tell tale bulb appears to be functioning - tested with a continuity tester and 9v battery - but does not display in the switch - I can't tell if the bulb comes on.

I have soldered a 12v LED light onto the board to replace the tungsten bulb and this works - it is bright. However, when placed into the switch to illuminate the symbol, the light given out is very dim. I cannot understand why it is so dim. I added a second LED to the outside of the switch just to confirm that all is working and it is bright.

Is there a minimum brightness required for tell-tale lights? I can barely see it even at night - I know that it is shining because I can see the glow from the side of the switch but the front is very dim.

If I place the second LED immediately below the switch, will this be sufficient for the MOT to confirm that the fog light is on or off?


This is the wiring of the switch. The fourth wire does not appear to have a feed or so anywhere although it is wired to.

I soldered the LEDs to the live feed in the corner of this picture and the neutral wire to the middle of the three solder bits.


If I replace this switch with another, what wires would I use for a 4 pin switch, Lx2 and Nx2? It appears that the switch has continuity when I put my circuit breaker probes against the two L pins or the two N pins when the switch is on. When turned off, the continuity is broken.

Many thanks,

I hope that this link will display the picture ...
https://www.dropbox.com/s/d15ibdlx3j50o ... 2.jpg?dl=0

[Bongolia]

Hi.
A tell tale is all that is required,it does not have to be an illuminated tell tale.
So you could paint the part of the rocker switch that is exposed when the light is on with a bright color paint like orange or white (tippex?)and that will be sufficient to allow the tester to pass it. If he queries that refer him to section
1.3 .Method of inspection;sub 1:b. This states
the presence and operation of the ‘tell-tale’.
Note: Some ‘tell-tales’ may be in the form of a coloured tag on a switch.
This will get you through the test.
In answer to the other question you could run the led out side of the switch and this would be acceptable also.
VW used the "tag" method for many years before switching,pardon the pun, to illuminated switches.
The current manual is on line here for your perusal.
https://www.gov.uk/topic/mot/manuals.
As to the wiring of your existing switch there are others on here better able to answer that part of your question.

[callum]

sorry for the hijack, but with the front fogs, is there a tell tale on switch or does it come up on the dash? I am retrofitting fogs but not all wiring is there, so am using original switch, with some original wiring but not all. Just curious!

[Matt&JoyBongling]

Thanks Bongolia. The switch is a full frontal push rather than a rocker so I will not be able to use tip-pex or similar to show that it is in but thanks to your info, a bulb will be installed below it. I will have a closer look at the regs as they didn't fail me on the front tell-tale light which I think has the same issue as the rear.

@Callum; my front fog light switch is next to the rear switch - both to the right of the steering wheel, next to the corner guide switch. There isn't a tell-tale on the dash - only, possibly, on the switch.

[Bongolia]

Hi Matt
That will do the trick.
Front fogs are not a testable item and so are not part of the MOT test.
So to Callum, it is not a requirement to have a tell tale for front fogs if you prefer not.

[Matt&JoyBongling]

Thanks @Bongolia

[callum]

Ah, excellent, good to know, thanks!