Hi Guys - hoping your forum can be of help ...

Mrs Gazzog was stopped by the police last night on here way home from work because her brake lights were permanently on !!

They said they'd seen this a few times with 500s

Anyhoo - I had a look this morning and found a switch dangling which operates the brake lights - the only thing is I can't see where or how it fits to the car - I'm guessing there might even be a bit missing !?

I'll try to attach a picture of what I have ...





Hopefully you can see the switch dangling in the top picture ?

Hi - I had this happen to our last 500. I found exactly the same piece in the passenger footwell and couldn't identify it. A week or so later I noticed that the brake lights were permanently on. This is the brake light operating switch and fits into a bracket on the rocker rod which runs across the car from the brake pedal to the master cylinder lever. You will find a loose wire dangling somewhere up under the dash in the passenger footwell. This actuating rod / bar is due to the adaptation of the vehicle from LHD to RHD and has been linked to passengers being able to inadvertently operating the brakes. I think (from memory) that you have all of it there.

Incidentally in our old car we had a weird hesitancy in the car, noticeable only when pulling away in first gear, in which the revs suddenly died off and would not pick up again. This bizarrely disappeared as soon as the switch was re-installed.

Just managed to take a rather fuzzy pic of the part in place on the bracket on the passenger footwell - I hope this helps!

Thanks for the replies - both are very interesting ...

The picture confirms where I thought the part would go but it also confirms that we are indeed missing a bit !

The car is second hand but was bought from a dealer and as such is still under their warranty - we had it in last week with a list of issues one of which was this loss of power as described above - the garage gave us the car back stating that they needed some parts (this is a Fiat garage btw) whilst explaining that the issue had something to do with brake lights but they didnt explain that this meant the lights were on all the time !!

My wife works with kids and uses her car to drive them around - I think that they have put her and their lives in danger !!

Thanks again - I'll let you know how this pans out !

Hi Gaz - I'm pretty certain you have it all there - if not the dealer should be able to sort it for you. The problem originally happened on our 2009 1.2 Lounge - the photo is of our replacement 2012 1.2 Lounge and as you can see Fiat have introduced a plastic shield to keep passengers feet away from the brake linkage and switch.

The associated loss of power on take-off in first gear was really baffling - I can only assume that there is some sensor or ecu override between the brake light switch and the throttle as a safety precaution or warning. It is interesting to hear that the police were aware of this as I could not find any info on the forum nor were two dealers aware of the issue?

I hope you get it sorted OK!

The brake light switch is used as an input to implement tip-in and tip-out 'smoothing'.

That means making the engine less 'lurchy' when coming on and off the throttle, particularly in a low gear. So with the brake switch being 'on', the ECM believes that you're decelerating, but this doesn't agree with the reading it's getting from the throttle pedal sensor, engine RPM sensor, and wheel sensors that the car is actually accelerating. Hence the strange behaviour.

Gazzog said:

I think that they have put her and their lives in danger !!

Thanks again - I'll let you know how this pans out !

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I wouldn't go that far. Whilst brake lights are an important safety light, you'd have to be a pretty poor driver not to be aware that a car in front of you is slowing down, and that the lights being on permanently indicates that you should exercise caution. Someone is just as likely NOT to be looking anyway and hit you regardless, whether the lights work or not.

However, if it IS the brake switch, it's pretty poor of the garage not to have fixed it.

I've had this problem twice with my 500. Each time loss of power when setting off and brake lights sticking. Dealer fixed under warranty first time then as goodwill the second. They did tell me the switch can not be put back in but instead has to be replaced. Not sure if thats the case or not but as i wasn't paying i didn't question. Seems a common fault.

Not a common fault if only a couple of people have had it.

Glad I found this thread. I've just started up the Cat C to turn it over and make sure the old battery is OK to move it around when I have the new windscreen fitted tomorrow and noticed that the brake lights are on permanently.

Will have a crawl in the footwell tomorrow. I'm hoping I've knocked something while fitting the new dash.

Does anyone know another reason. My switch is connected! I disconnected the plug and took the switch out but when I've put it back together the brake lights are still on! Faulty switch maybe?

Read online that the plunger part can get stuck and to reset you have to pull it out with a pair of pliers so will give that a try tomorrow. Failing that there are loads of them on eBay for about £9

typecastboy said:

Read online that the plunger part can get stuck and to reset you have to pull it out with a pair of pliers so will give that a try tomorrow. Failing that there are loads of them on eBay for about £9

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I'm guessing maybe someone stood on the brake pedal pretty hard just prior to impact!! I wonder do they get forced on by the Ecu during a high impact and need resetting?

Mercky said:

I'm guessing maybe someone stood on the brake pedal pretty hard just prior to impact!! I wonder do they get forced on by the Ecu during a high impact and need resetting?

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You could well be right, I know I would be standing up on the pedal in a crash, just waiting for that horrible sound of metal on metal.

Hopefully the reset will work. Don't think the ECU does anything to it.

It may well have been like it all along but I don't recall it when I first got the car. I may well just not have noticed.

Yeah it worked, took the switch out. Pulled the plunger out until it clicked with a pair of pliers, put it back in, connected the switch and it's now working as it should.

£9 saved! Phew!!

Just to confirm this thread helped me with my wife's 500 red convertible.
She had been stopped by the police with allegedly brake lights constantly flickering..... when I tested, no replication of issue. Then she started having the "hill hold" warning coming on intermittently and impacting upon acceleration - battery charged and disconnected and warnings reset again saw no obvious cause.
So it was a random fault which came and went.....

So far having replaced the switch all is good. Interestingly there was absolutely no clear sign of the original switch being dodgy but i guess it was the 2009 original.
Let's hope all remains good - next test for me is on my daughter's yellow 500 (no lights for the dash behind the heating and ventilation controls......).

soundrediscovery said:

Just to confirm this thread helped me with my wife's 500 red convertible.
She had been stopped by the police with allegedly brake lights constantly flickering..... when I tested, no replication of issue. Then she started having the "hill hold" warning coming on intermittently and impacting upon acceleration - battery charged and disconnected and warnings reset again saw no obvious cause.
So it was a random fault which came and went.....

So far having replaced the switch all is good. Interestingly there was absolutely no clear sign of the original switch being dodgy but i guess it was the 2009 original.
Let's hope all remains good - next test for me is on my daughter's yellow 500 (no lights for the dash behind the heating and ventilation controls......).

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An even easier fix than the brake light switch.

Turn all the dials as far as they will go either way. Get a plastic tool or two behind the panel and prise out. It’s well held in but will eventually pop off. There are two little bulbs one for each side plus a separate one for the A/C switch. Change the two bulbs and making sure the knobs are still where you turned them to, push the panel back on.