Technical Brake lights stopped working

[squixs]

Hi all,

I'm running into an issue with my Fiat 500 1.2 from 2009.
The instrument cluster is displaying an error message: "Check brake lights," and I can confirm none of the three brake lights are working.
I've already changed the brake light switch sensor, this fixed the problem initially, but after a week, I got the same error. Lights are back to not functioning.

The weird thing is: Every time I press the brake pedal, a "squeak" like sound is heard from somewhere in the dashboard.

Any tips and tricks?

Thanks!

 

[John202020]

Hi, first check the wiring going to the tailgate boot lid at the flexible then check the fuse.

 

[squixs]

Thank you for your reply.
I've replaced the wiring in the tailgate boot, since most of the cables were indeed busted, causing things like the rear wiper to malfunction.
I reviewed the wiring diagrams, but I can't find whether the wiring for the brake lighting is going through the tailgate boot flexible part. Can you confirm this?
I've checked the fuse, this is OK.

 

[chris3234]

The 3rd brake light likely is but not the others


If you have multi ECUscan I'd check to see if it shows the brake switch as being active when you press the pedal down

If it is the bcu should be supplying power the the lights the brake switch shouldn't be the cause again you'd hope but it could be that it was a dodgy part on not installed quite right


On you models it's behind a cover plate on the passenger side of the car as the brake are operated via a large steel level/rod from the drivers side

Thank you for your reply.
I've replaced the wiring in the tailgate boot, since most of the cables were indeed busted, causing things like the rear wiper to malfunction.
I reviewed the wiring diagrams, but I can't find whether the wiring for the brake lighting is going through the tailgate boot flexible part. Can you confirm this?
I've checked the fuse, this is OK.

 

[varesecrazy]

Thank you for your reply.
I've replaced the wiring in the tailgate boot, since most of the cables were indeed busted, causing things like the rear wiper to malfunction.
I reviewed the wiring diagrams, but I can't find whether the wiring for the brake lighting is going through the tailgate boot flexible part. Can you confirm this?
I've checked the fuse, this is OK.

Try plugging your old switch into the loom..while in your hand

Squeeze the switch.. do the lights work ?

 

[A3jeroen]

Did you replace the switch the right way? I.E. pull out the pin, lift the pedal, mount the switch and slowly let the pedal push in the pin.

gr J

 

[jrkitching]

I reviewed the wiring diagrams, but I can't find whether the wiring for the brake lighting is going through the tailgate boot flexible part.

The wiring for the 3rd (high) brake light obviously goes through the suspect hatch wiring. Any short here will likely take out all three.

I've replaced the wiring in the tailgate boot, since most of the cables were indeed busted, causing things like the rear wiper to malfunction.

How long ago did you repair it, and what type of wire did you use?

It's not unusual for this wiring to fail again. Plenty of folks here are now on their third or fourth repair.

 

[varesecrazy]

With their being a 'strange sound'... from the dash area
I still would test the switch action before pulling wiring looms apart

 

[jrkitching]

With their being a 'strange sound'... from the dash area

I'm wondering if this could be a relay which is tripping as a result of a wiring fault.

 

[varesecrazy]

I'm wondering if this could be a relay which is tripping as a result of a wiring fault.

Could be..

Or a poorly mounted switch not making a smooth operation.. just a creak

 

[varesecrazy]

Thank you for your reply.
I've replaced the wiring in the tailgate boot, since most of the cables were indeed busted, causing things like the rear wiper to malfunction.
I reviewed the wiring diagrams, but I can't find whether the wiring for the brake lighting is going through the tailgate boot flexible part. Can you confirm this?
I've checked the fuse, this is OK.

Any progress with this?