BCU photo. For those who have the same issue and are following this story. Other posts and youtube video show a guy with the same issue on a Fiat 500. He also butchers the BCU which on his model is a single board (not dual layered) so he can easily access the rear of the relay solder connections and replace the relays. Again plenty of other posts talk about sourcing these from any supplier and simple solder them on. The point to note is that the BCU's look identical between most models- but they are not. On this guys BCU the relays he identifies as lights related are the two not visible in my photo. Those were of course the first 2 i went after assuming the same issue (relay simply stuck on) and therefore solution would be as set out in his video.
Technical Lights won't turn off!
- Thread starter PaulyMcPaulFace
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Technical Lights won't turn off!
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Interesting.
Those relays look small and they could easily weld themselves together with the high instantaneous current of filament bulbs. One more advantage of LEDS!!!!
Those relays look small and they could easily weld themselves together with the high instantaneous current of filament bulbs. One more advantage of LEDS!!!!
Certainly not an MOT fail. The MOT requires that the lights come on, which they do. And and as someone else said, I cannot drive my Volvo without them on.
It seems most of the ‘high current’ relays are in that relay box by the battery so i’d guess (and it is only a guess) that’s where you need to be looking.
It seems most of the ‘high current’ relays are in that relay box by the battery so i’d guess (and it is only a guess) that’s where you need to be looking.
Two of those relays by those controlling washer jets (took me a while to work out what ‘skoosh’ was!!) are probably for the wiper motors front and rear. On ‘intermittent’, you can hear them ‘tick’. And likely also the flasher (indicator) is a relay in there too (the ‘tick tick’ you hear when signalling is actually an elecronic sound from a loudspeaker (if you unclip the seatbelt while indicating, or very lightly apply the handbrake, the beeper that sounds is heard in place of the ticking)... There are 7 relays on here. 6 bigger and 1 smaller. I've opened them all up. Inside each of the bigger ones is a double relay. I've identified the function of all but two, which coincidentally are located beside the other two that are washer jet operation...
I'll post a photo of BCU butchered as described, may at this point help someone questioning whats inside the bcu
Thanks for this. So a few points.
1, mot comment. My thoughts also but if theres a switch and they should be switchable and they aint??????
2, bcu relays. I though the same as you but nope. Rear and front wipers dont use relay and heater/ blower doesnt activate the last two relays on bcu either. I assume these are in engine bay fuse box.
3, engine fuse box. Agree this is where the big relays live. Pulling them all but one (not all at the same time) doesnt cut the lights! The one 20amp relay that does kill the lights, also kills all power to all systems at same time.
4, now those little relays are cut open and i can tap them to activate and hear them click away under normal operation. Listening intently, theres no click, tick or signs of movement innreaponse to indicator operation! The indicator sound is speaker operated though. So could we be looking at a mk3 vs mk4 variation here?
Baffled by the logic of this althought i have located the wiring diagram which although for a mk3 2012, looks more like the mk2 with dual inline fuses(f24 and 15), one for each headlight. Please keep the suggestions coming folks. I think im still searching for the light relay! Really would benfit from knowing if multiscanecu will activate low beams to allow testing?
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No problem
You are adding great knowledge about these things.
Last FIAT I had to look BEHIND glovebox was 20 years ago..
MES..I doubt it..
But my set.up is 100 miles from the car
I own a lot of the cables.. but not quite that many..
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Cheers, either that or giving folk a good giggle at stupidity! Update as follows.No problem
You are adding great knowledge about these things.
Last FIAT I had to look BEHIND glovebox was 20 years ago..
MES..I doubt it..
But my set.up is 100 miles from the car
I own a lot of the cables.. but not quite that many..
1,mes (multiscanecu) does indeed allow testing of low beam actuation. This will quickly rule out conclusively the switch to be at fault as the software will mimic the switch. Surely someones done this test before then? What was the result?
2,still looking for that lights relay if anyone want to switch on and listen to where the click comes from??? Any takers??
3,anyone local (fat chance!) with elm and yellow cable i could borrow to test using mes?
Hi all. Little update on progress (or lack off). So multiscan cables arrived and i can operate diagnostics...yeah. So what ive found is.
1, the lights switch on and off with multiscan test. Suggests no duff relays then.
2, varescrazy confirms no click when operating which aligns with what i think. Lights on this model are bcu operated. No relay or step up circuit.
3,multiscan says the error is an open circuit and switch is faulty.
4, testing switch on multi scan it goes from auto to on when operating light control. So suggests switch works fine as status changes. However, i dont like the 'auto' status. Id expect it to say off.
5, disconnecting switch and testing the fault remains as open circuit. So essentially the bcu doesnt think the switch is connected, even though the switch seems to function.
6 with the lights off and power off. Turning the light switch on activates the day time running lights!!! Is this normal?
Catman similar issues. Yeah a good few folk have had this issue. Problem is few update after fix so is it a switch or fiat garage doing software upgrade ( which noting the lights are bcu operated, this could be the issue). Theres one post on here where the stalk switch is replaced, no change and a software update via fiat seemed to solve the issue... Albeit again not confirmed.
So anyone any other ideas? Im about to buy another switch unit just to rule it out. After that its dashboard out and wire wiggling! Help!
Also mot guy says it would be a fail if not fixed.
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For info - In normal operation
If the ignition is off, and the light switch was left 'on', turning switch from 'on' to 'off' then to 'on' again will turn on the parking (side and tail) lights (not the DRLs but the less bright side light in the same bulb)
If the light switch was in the 'off' position with ignition off, I think you have to turn to on, off and on again to put the parking lights on.
If the ignition is off, and the light switch was left 'on', turning switch from 'on' to 'off' then to 'on' again will turn on the parking (side and tail) lights (not the DRLs but the less bright side light in the same bulb)
If the light switch was in the 'off' position with ignition off, I think you have to turn to on, off and on again to put the parking lights on.
Have you read this earlier thread?
https://www.fiatforum.com/panda-iii/443073-dipped-headlights-always.html
And this too, especially post 9 of the thread that says solution was new (presume with different 'internals' switch, AND the computer being updated to recognise the new switch. This apparently happened after a software update 'caused' the issue.
https://www.fiatforum.com/newbie-central/436049-headlight-recall.html
https://www.fiatforum.com/panda-iii/443073-dipped-headlights-always.html
And this too, especially post 9 of the thread that says solution was new (presume with different 'internals' switch, AND the computer being updated to recognise the new switch. This apparently happened after a software update 'caused' the issue.
https://www.fiatforum.com/newbie-central/436049-headlight-recall.html
Hertshillhopper. Thanks for confirming light operation. Thats most useful and suggests light switch is working just fine. Regarding the post links. Sure ive been through them all!!!! The problem is for someone in my position that cant have this fixed for free im trying to sort this out myself and hopefully help others with the elimination process. All the posts suggests different solutions from new stalks, programming, new bcu. Relay replacement on ecu, realigment to a rain dance. Battery diacharge, battery recharge to fingers crossed. This all following multiple visits to fiat garage. Throw into this the variation in model and seemingly consistently poor fiat technicians with wide palms. I am rapidly moving to a conclusion its software related. But how can this be?
For reference i had the car 1 day with lights working the one time i checked them. I have not done any miles in the car yet. Working one minute and now they wont!
Please do keep the advise coming. I do think im nearing a conclusion.
I was sure you’d have read them - but not necessarily mentioned them. It *does* look like Fiat do a ‘try everything’ and ‘stumble across’ the fix. I don’t believe you need a new switch. The ‘red herring’ there is that on the previous (169) Panda there were a number of failures of the switches (which did use relays etc for the lights), where the switch ‘innards’ would fail and leave a driver in the dark. The switch on the later Panda is physically different.
Come back to your MES findings. You said it shows the switch changing from ‘on’ to ‘auto’. The Panda hasn’t been offered (so far as I know) with auto, light sensing headlights (where they come by themselves on if it gets dark), but your comment suggests the computer is capable of supporting that function. (Similarly, so far as I know it’s not been offered with rain-sending wipers, yet there’s a warning light in the dash to show the wipers are in ‘auto’ mode. I’ve never used MES, but I wonder: is there an option to say ‘auto light sensor not present’ somewhere?
Come back to your MES findings. You said it shows the switch changing from ‘on’ to ‘auto’. The Panda hasn’t been offered (so far as I know) with auto, light sensing headlights (where they come by themselves on if it gets dark), but your comment suggests the computer is capable of supporting that function. (Similarly, so far as I know it’s not been offered with rain-sending wipers, yet there’s a warning light in the dash to show the wipers are in ‘auto’ mode. I’ve never used MES, but I wonder: is there an option to say ‘auto light sensor not present’ somewhere?
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Anybody like to see if there is a click:clonk when main headlights are switched..
I did in my 2013 but would be good to know I'm not deaf..
Charlie
I did in my 2013 but would be good to know I'm not deaf..
Charlie
Ah - no there’s not! (Just been and shone a torch across the instrument panel) But there was on the old 169 model. There are though all sorts of ‘hidden’ symbols for things I’ve not got
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I dont think its a auto function thats disabled etc. Mes can test live sswitch status. When switch is on, it says on, when switch is off it says 'auto'. Whats interesting is when i disconnect the switch completely its status then goes to off. So it suggests to me switch is operating fine. I understand that on thia model if the bcu doeant detect a 3v signal from the switch it defaults to lights on. So essentailly the light switch actually stops the signal to switch the lights on. So the auto may refer to the fact that its leaving the bcu to decide to activate lights.
Im pretty much out of ideas now to test. If i can get a cheap switch unit its worth a try but i think im going to have to take it to fiat and play the bullsh+t lottery with them!
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Hi.
Someone with the knowledge and time could reverse engineer a suitable program for re-programming.
When I had the Rover 75's the Rover system was a "T4" I had one and it obviously could do anything from coding in units to every test you could imagine but the Poles came up with a reversed engineered system called TOAF.
To be fair the Polish system ran spots off Rover's T4. OK I accept that newer cars have more complex systems but its not outwith the realms of possibility to do this. Perhaps MES could be even upgraded for more features.
Someone with the knowledge and time could reverse engineer a suitable program for re-programming.
When I had the Rover 75's the Rover system was a "T4" I had one and it obviously could do anything from coding in units to every test you could imagine but the Poles came up with a reversed engineered system called TOAF.
To be fair the Polish system ran spots off Rover's T4. OK I accept that newer cars have more complex systems but its not outwith the realms of possibility to do this. Perhaps MES could be even upgraded for more features.
