Technical Retrofit a "headlights left on" warning buzzer on canbus system/Panda 312

[Jamie KC]

Having recently become a Panda owner in the late summer months, I am now discovering a potential flaw in the autumn/winter months. I frequently get in the car in the morn to find the headlights still turned on. 80% off the time it is my wife leaving them on when the car is turned off, but sometimes I am also guilty of this.

Yes, I agree that in some ways it is a masterstroke by Fiat that when you switch the ignition off the headlights also go off. But I think there is the scope to kill bulbs faster too. When you switch the ignition on, then proceed to start the car, you'll notice the lights flicker on and off. This flickering can't realistically be good for the longevity of a bulb, particularly in the frequently low winter temps here in the north.

I've uprated the bulbs to Osram Nightbreaker 200s, so their working hours is shorter vs a normal H4, and the cost higher, so I'm keen to maximise their lifespan. It's unlikely that the wife will find the discipline to switch them off whenever exiting or entering the vehicle, so retrofitting a buzzer is the best option.

It needs to activate only when light switch on, ignition off, door open. Or even just light switch on, ignition off, irrespective of door. How easy/tricky is this on a canbus system?

*Originally posted in the Tech Talk forum, as I thought it a relevant issue to a number of different models, has been moved to Panda (presumably because of title)

 

[Herts Hillhopper]

There is the green ‘lights on’ light…

 

[Herts Hillhopper]

...When you switch the ignition on, then proceed to start the car, you'll notice the lights flicker on and off. This flickering can't realistically be good for the longevity of a bulb, particularly in the frequently low winter temps here in the north.

I've uprated the bulbs to Osram Nightbreaker 200s, so their working hours is shorter vs a normal H4, and the cost higher, so I'm keen to maximise their lifespan...

Flickering as the starter turns is not likely to damage the bulbs (but might show your battery is less than tip top condition)... Hitting a bump or a pothole with the lights turned on is much more likely to damage the filament, but even then they're pretty robust (my 150% brighter lights have survived 49000 miles of driving so far)

 

[Jamie KC]

There is the green ‘lights on’ light…

That goes out as soon as the ignition is switched off, so requires greater observation skills than the wife has to spare when arriving home, still listening to podcast, arguing with the kids etc as pulls up and turns key.

Good to know they last well in your Panda, hopefully I’ll have the same experience. In the Galaxy and the Meriva I’ve been used to replacing a bulb in each one about once a year, roughly 10-15k apart.

I’ll check the battery voltage out, but it’s a relatively new looking genuine Fiat stop/start effort, and seems to spin everything over just fine. Never seems sluggish or hesitant, but DRL and interior lights do flicker for that second or so of cranking. Do your interior lights stay steadily lit when cranking?

 

[Herts Hillhopper]

I’ll check the battery voltage out, but it’s a relatively new looking genuine Fiat stop/start effort, and seems to spin everything over just fine. Never seems sluggish or hesitant, but DRL and interior lights do flicker for that second or so of cranking. Do your interior lights stay steadily lit when cranking?

yes - all lights stay on fine. But it starts in an instant so maybe never really noticed
Does your stop/start work ok? Generally that choosing not to operate is early sign of unhappy battery.

 

[Jamie KC]

yes - all lights stay on fine. But it starts in an instant so maybe never really noticed
Does your stop/start work ok? Generally that choosing not to operate is early sign of unhappy battery.

Stop start has always been behaving deftly in this vehicle. It stops and then fires up again after about 10secs, so I’ve switched the function off. This is whether it’s 5deg or 25deg out, whether engine slightly warmed up or properly warmed up.

Battery voltage this morning was 12.25, which I would say is acceptable. Run home last night was 30mins with lights and heaters on. Once started I get a steady 14.4v at the battery terminals, so this suggests correct alternator function. It hovers around 14.2 to 14.4 whilst driving.

Attached vid of interior light dimming. These are LEDs but was the same on the original bulbs too. As you can hear car starts straightaway, first start of the day in 5deg temp.

 

[The Panda Nut]

My daughter leaves the headlights on on the 169, The +25% night breakers have been in for 5 years. Just had to replace them as the one that was mucked about with the headlamp change just failed. I dont think it will make a huge difference to bulb life but you never know. All 3 Pandas sit at 12.8 volts in the morning so I should watch the battery. After two batteries failed both showing 12.2v I dont trust them any more.. Another thing the manufacturers have messed up....

 

[chris3234]

Stop start has always been behaving deftly in this vehicle. It stops and then fires up again after about 10secs, so I’ve switched the function off. This is whether it’s 5deg or 25deg out, whether engine slightly warmed up or properly warmed up.

Battery voltage this morning was 12.25, which I would say is acceptable. Run home last night was 30mins with lights and heaters on. Once started I get a steady 14.4v at the battery terminals, so this suggests correct alternator function. It hovers around 14.2 to 14.4 whilst driving.

Attached vid of interior light dimming. These are LEDs but was the same on the original bulbs too. As you can hear car starts straightaway, first start of the day in 5deg temp.

12.25 actually means it is only around 50% charged

 

[Jamie KC]

12.25 actually means it is only around 50% charged

Well buggrit.

 

[Herts Hillhopper]

Yes - fully charged and then read after 6 hours or so should be 12.7 or 12.8v

12.5 = half charged

12.2 = battery not good.

If stop start turns back on after brief pause that shows the voltage sensor is aware the battery’s not so good and restarts while it knows it can

 

[Herts Hillhopper]

I took another look...
In the summer I don't notice but yes the (also Fiat LED) interior light does dim momentarily on starting - but not flicker in the way yours does.
In this colder weather, the interior light has gone off by the time the glow plugs are ready, so don't see it happen then.
The headlights do dim a little too, but again I wouldn't call it flickering, just a tad less bright while the starter turns.

 

[A3jeroen]

I drive Fiat's since '92 and have always left the lightswitch on on. Never had a problem with them.

gr J

 

[Marcus Daly]

Automatic headlights are one of the things I miss from the "grown up" cars I ran prior to the Panda. I still forget to switch them off, three years later.

One thing I always remember to switch off is stop/start—first thing I do after I start the car.

 

[Herts Hillhopper]

One thing I always remember to switch off is stop/start—first thing I do after I start the car.

Why? It works beautifully… and intelligently turns itself off when it needs to

 

[Marcus Daly]

Why? It works beautifully… and intelligently turns itself off when it needs to

Less strain on the battery = longer life.

 

[A3jeroen]

As an aside... The buzzer will only buzz when the lights are on when opening the door. Since in a Fiat they turn off on ignition, the buzzer will never make a sound...

gr J