Technical Problem with "electronic check" of brake lights

[fiat1100d]

Hi!

My Tempra has a strange behaviour of the "electronic check", regarding the "broken brake lights" indicator. It has the digital dashboard of course.
The light on the computer will turn on after releasing the brake pedal, even if the brake lights are working just fine. It started to do this in wet days, so I thought about some electrical contact problem in the lamps, but now it seldomly does this even in dry days.
Strange issue is that, if I press the pedal when the "broken lamp" light is turned on, then when releasing it could turn off. It seems that, depending on how I press the pedal, the computer recognizes the brake lamps as broken or working...

Where is the sensor located? Could some cleaning with a spray for electrical contacts help?

Thanks!

 

[cro_gandalf]

try to change lamps. put new, it could help...

ant this electronic check is working by comparing resistances.

example:
few of my friends have (let's say) the same problem. they have changed standard wolfram bulbs with LEDs. resistance of wolfram bulb is around 35 ohms. resistance of LED light is 800 ohms. and computer (or electronic check) is thinking that you have broken lamp there...

i hope that could be helpfully

 

[fiat1100d]

Thanks for your tip, but I don't think lamps are the issue, their resistance shouldn't change a lot during their life.

A guy in the Tipo section told me that it could be the "earth strap" for the lights that should be located in the boot, that may need some cleaning: if I correctly understood, that should be where the earth cables of lamps connect to. Do you have any idea of where it exactly is on the Tempra?

P.S. for your friend with LEDs, connecting a resistance of proper value and power in parallel to the LED lamps should solve the problem with the computer

 

[cro_gandalf]

i don't know where is earth point located in the trunk. i'll take a look tomorrw.

proper resistance for leds is 39 ohms, 5 W (ceramic resistor)

 

[Ziomike]

My Tempra has a strange behaviour of the "electronic check", regarding the "broken brake lights" indicator. It has the digital dashboard of course.
The light on the computer will turn on after releasing the brake pedal, even if the brake lights are working just fine. It started to do this in wet days, so I thought about some electrical contact problem in the lamps, but now it seldomly does this even in dry days.
Strange issue is that, if I press the pedal when the "broken lamp" light is turned on, then when releasing it could turn off. It seems that, depending on how I press the pedal, the computer recognizes the brake lamps as broken or working...Thanks!

As you say "depending on how I press the pedal, the computer recognizes the brake lamps as broken or working".

It is not earths
The problem is with the brake light switch on the brake pedal, it's going faulty. I've had this and checking the Tempra workshop manual it says the computer monitors the brake lamps as well as the switch.

I have some diagnostic info here - www.brickfieldspark.org/temp/fiatmanuals/temprainfo.htm - bottom of the page go for link - "Check, diagnosing faults - 4" - it's a pdf file, bottom of that page there are 2 blocks for "The brake warning light stays on ......", gets a bit technical but right at the bottom of the page is "brake light switch is defective - replace".

Other pages there describe the "Check" circuits and the locations of parts in the car, you will also need to look at the top link - "Wiring diagram legends" - for the parts numbering on the diagrams.

Faulty brake lights will show an error light when you PRESS the brake pedal.
A Faulty switch will show an error light when you RELEASE the brake pedal.

Occasionally "jiggling" the brake pedal will make the error go away - it's the switch.

You can remove the switch and clean it (I did) but this will not last long, long term replace the switch, it is a common component accross the Fiat range, if its not available one from a Tipo will do, although my local dealer was able to get one easily.


Changing brake lights for the newer LED replacements may need some additional resistance as the computer Check circuit will see higher resistance LED lamps as open circuit or defective lamps.

 

[fiat1100d]

Ziomike, thanks for your reply, very useful! Will have a look at the switch then, try to clean it and eventually replace if the problem goes on.

 

[Galilio_Mad]

i had the same problem
it turned out to be the Brake pedal switch, tried cleaning but didnt work
i replaced it and its all ok now

 

[fiat1100d]

i had the same problem
it turned out to be the Brake pedal switch, tried cleaning but didnt work
i replaced it and its all ok now

Did see on ePer that the switch costs a bit, about 13 euro, so for now I literally washed it with contact cleaner... Did spray a lot into the switch... But as soon as I will see red lights again on the dashboard, from brakes, the old switch will go!