Surely the tiniest MoT failure ever... but I'm struggling to fix it.

[brownnova]

My MX5 MoT test was this week. It failed...

 

But on the most tiny and ridiculous thing I have ever heard of. My fog light has no tell tale for when it is on.

 

This is now the only thing standing between me and another years happy motoring. But of course as it's an import it's foglight was fitted aftermarket. The switch used had no tell tale. In a rash moment I bought a fancy new proper Mazda switch...

 

However whilst this has a light in it. It refused to illuminate. So problem not solved. Upon closer inspection the switch has 5 connectors and the car only four. Sone googling later found that mine was lacking the wire to compete the circuit for the tell tale. What appears to be the Right wire found and.... tell tale on! Regardless of whether the fog light is or not. Bollocks!

 

So I'm kinda stumped. My foglight operates with the switch whether the car is on or not. Which doesn't seem right to me. But still actually using the switch should be the trigger for the tell tale.

 

Any ideas/help most welcome as it's really doing my nut in to be honest!!!!

[gadgetgricey]

Can a temp rotary switch be fitted.

One that has a clearly labelled on and off position, or does it have to illuminate?

 

Gets you the MOT and gives you 12 months to sort out a more fitting option.

[Faker]

Can't help... but I'd somewhat of a similar silly failure once...

 

I'd a 1996 mini cooper spi. Car was mint... I sold it 6/12/2005 after 2 years ownership. Car was a genuine norn iron car. Never hit. Never damaged. Stone mint. I was the second owner after a work colleague. Car failed mot with me.... for having the fog light on the wrong side.... now... I raised this with the mot examiner (in norn iron mot is run by government and examiners are civil servants), explaining the car was totally original, never damaged or painted, and as it left the factory. He told me it must have been a Friday afternoon car! It's fog light was on the left, and not the right! I had to take it away and fit one to the other side to get a pass!!

 

PS.. I fitted the cat back stainless centre exit!

[STUNO]

Me thinks you have wired it in back to front with a permanent live going to the telltale lamp instead of the switch.

live to switch, switch "on" to lamp then to earth, or something similar.

Or maybe someone who knows can help !!

[Conrad D. Conelrad]

I had this problem. Foglight switch had been replaced with a blank generic rocker switch. The telltale doesn't have to be illuminated. I cut a small piece of red electrical tape and stuck it on the part of the rocker which is only visible when it's on. Passed. 

[gm]

I had the same problem so bodged a mini led in the gap down the side of the switch, in a very similar way to how I've bodged this heated rear screen switch

 

 

Thinking about the wiring for your switch, you will have an extra pin to the right of the four on this switch

 

 

the two on the left are for the backlighting (one is to live, the other to ground)

 

the lower middle is for your live feed, the upper middle goes off to the foglight (these may be the other way round, I'm doing this from memory at 4am (but at least I'm not pissed)) and the (invisible) upper right goes to ground to illuminate the telltale.

 

Mazda buggered about with that area of the loom several times so it's not always a case of plug and play - there are three different types of heated rear screen switch for the mk1 alone, all with different wiring configurations - crackers !

 

Hope this helps

[The Reverend Bluejeans]

Halfords sell illuminated toggle switches.

[Richard]

The tell-tale doesn't have to be in the switch, does it? I've certainly had cars where it's in the instrument panel. A generic warning light connected to the output should do, or you could buy something like this that comes with the correct symbol. 

 

https://www.ebay.co.uk/itm/8-10-12-16MM-LED-DASH-PANEL-WARNING-PILOT-LIGHT-INDICATOR-MOTORSPORT-TRACK-RACE/253175542261?hash=item3af27031f5:m:mfTwziJ9WI0yteWCnCR46gQ

 

 

Just an example picked at random, there are dozens of options on eBay.

[Shirley Knott]

On various imported MX5's I've had to install fog lights (They don't have them fitted in the land of the rising sun) and I've never had an issue with no tell tale on the switches MOT wise. Perhaps my tester is lenient? Either way I think you've been slightly unlucky.

 

As others have said, buy a generic light/switch and have at it

[SiC]

It's a rocker switch. Surely the fact that it's at an angle means that it's on?? Failing that, connect the illumination pin on the switch to the pin that goes to the light itself.

[Tamworthbay]

This ^^^^^^^^ find the live output and run a loop to the telltale input and job done. Or run the permanently on feed into a relay and use the output to switch it, dead easy to do with a £1 relay.

[blackboilersuit]

Me thinks you have wired it in back to front with a permanent live going to the telltale lamp instead of the switch.

live to switch, switch "on" to lamp then to earth, or something similar.

Or maybe someone who knows can help !!

 

^^^^^^^ This sounds right to me.

 

The 5 wires will be ....

 

Two for the backlight, not the tell tale but the lamp that lights up the whole switch so you can see it at night.

Power in and power out for the fog light.

Ground connection to the tell tale light.

 

The tell tale takes its power internally from the fog light power out terminal of the switch. As STUNO describes if you have fog light power in and out connections reversed then the foglight will still work but the tell tale will be on all the time.  

[johngarty]

Is Tell-Tale really a motoring term? Never heard that one if so, What do they use in USA? = Snitch?

[brownnova]

I had this problem. Foglight switch had been replaced with a blank generic rocker switch. The telltale doesn't have to be illuminated. I cut a small piece of red electrical tape and stuck it on the part of the rocker which is only visible when it's on. Passed.

I'm thinking this type of solution might be worth a try...

[brownnova]

On various imported MX5's I've had to install fog lights (They don't have them fitted in the land of the rising sun) and I've never had an issue with no tell tale on the switches MOT wise. Perhaps my tester is lenient? Either way I think you've been slightly unlucky.

 

 

I've never had this problem in any of the previous MoT tests either.

 

My new switch does have a light it just won't light up at all or will light up all the time. But nowhere in between!!!

[brownnova]

The bavk of my new switch with the tell tale looks like this...

 

But the bit that receives it (I don't know it's proper name- I'm a bit clueless on electrics) has only 4 connectors not the 5 pins like the switch...

 

My research showed that the dimmer for the dash lights was also supposed to provide the power for the tell tale. So I wired the blue wire here into the connection thingy and that's when I got permanent light on the tell tale.

 

Who knows if that's right... frankly I have got less of a clue on electrics than Kim Jong-un has on democracy.

 

Anyway the switch looks lovely...

 

 

But still no MoT passability...

[loserone]

I had this problem. Foglight switch had been replaced with a blank generic rocker switch. The telltale doesn't have to be illuminated. I cut a small piece of red electrical tape and stuck it on the part of the rocker which is only visible when it's on. Passed.

I did this on my mx5. Chap was very happy with it.

 

He wasn't so happy with the ice-cream container covered sill ends, but he couldn't do anything but pass and advise.

[carlo]

You could always try another MOT centre, explain the issue first and see if they mind or not?  Might save some hassle.

[loserone]

£50 mot for the sake of a bit of red tape?

[Pillock]

Also it's a valid fail. Pedantic, but valid. So another MOT place would surely give the same result, especially when they look at the MOT history and see you've not fixed it.

 

If it's a rocker, a bit of red nail varnish on the bit that's exposed when it's on.

 

Failing that, I can post you a 12V LED on a length of wire. GM above knows which wires are foglight and ground so across there will illuminate when switch on. Dangle it out of the dashboard, get MOT, rip it off again and sort something more permanent later.

[Guest Hooli]

As others have said, it seems like rather than wire the tell-tale to the dashlights it needs to go to earth.

 

Should be easy enough to prove with a test lamp/meter/bit of wire.

[steveo3002]

run a bit of speaker wire from the terminals to a 12v led and tape it the dash to get a pass , then research how to make a neat job of it later

[Guest Hooli]

It'd take longer to bodge than do correctly in my experience.

[PiperCub]

I think you've got it wired a bit barse ackwards. But for the moment, as said, buy a simple illuminated switch (as RBJ says), bang that in series, when you switch it on then the whole thing will light up - sorted, MoT out the way.

 

Then once MoT'd, you can check the connections and marry them up with the switch. What I'd recommend is probe each connection, check what it's doing with lights off, lights on with fog lamp off, lights on with fog lamp on. That way you'll know what does what. Then check continuity of the switch and see how it's wired. If the terminals are labelled with numbers, check this again the wiring diag in the manual. 

 

The fact the switch has five conns but the loom only four may be a red herring. The switch is probably used on numerous Mazdas not just the '5 and the loom for the car will almost certainly be common for all countries - it isn't worth producing different looms as a rule so if one or two will suit the whole range for a given model year then the unused cables/conns will be tucked away. the fact that you don't need a fog lamp in Japan (or USA - Miata) but do in Europe is a good case in point, it'll be in the loom as the cars are all produced on the same line so they just fit a fog to European cars but not to JDM & USA cars but the wiring will be there. It's worth checking the manual on this. 

 

As a serial '5 owner, I've got a UK spec 1990 NA (Mk1) and used to have a '92 Eunos, both switches were the same, both illuminate the same even though the UK one has a fog as standard (& bumper to suit) whereas the JDM car had an obviously retro fitted affair (that I broke off twice!). 

[loserone]

I've no idea why wiring is involved. Having an led is not going to affect the driving experience even a tiny bit.

[Guest Hooli]

It's so you've no excuse for driving around with the foglight on all the time like those wankers who like to use them in rain.

[MikeR]

might be the 3 terminals in a row are a change over switch , with the middle connector being the common ?

 

and the 2 on their tod are the light ) tell tale ?

[brownnova]

It'd take longer to bodge than do correctly in my experience.

Agreed...

 

I'm going to try red tape, take it in on Monday and ask if that'll do.

 

If not I'm sorting it properly. I shelled out for the proper part (which is unusual for me... I must like this car!) So I'll get it to work properly!!!

[PhilA]

Might want to check if there light goes out of you pull the bulb out of the fog light.

 

If it's wired backwards it'll just ground through the bulb.

 

Phil

[brownnova]

This is what I've been using as a guide to the pins and wires...

 

 

So the fifth pin should be connected. By my amateur hour electrical knowledge is preventing me from knowing which wire does what...