Technical Brake light fail indication but all stop lights working

Currently reading:
Technical Brake light fail indication but all stop lights working

The Body Computer is the grey box attached to the back of the dashboard fuse box.
.
 

Attachments

  • Fuse Box & BC.jpg
    Fuse Box & BC.jpg
    43.2 KB · Views: 64
The measured resistance from the white multiway you have shown to the C30/31 earth studs is 0.1ohm, this is identical to a measurement between two scratch marks on opposite sides of the boot floor, so assume that is OK.

Poor quality multimeters are never very good at measuring very low resistances. Assuming you have a reasonable quality multimeter, it should read 0Ω between different parts of the body. If you have a digital meter, it should auto-zero but poor quality ones often don't zero accurately. If you have an analogue meter, there should be a zeroing adjustment wheel on it for the resistance scales.

As I sit here I have noticed a double sided nail file board and wonder should I se that to roughen the contacts surface?

A nail file or emery board will be too thick for the female contacts and could force them further apart. It will also remove any gold, silver or cupro-nickel plating from the contacts. It may cure the problem temporarily but the problem would return once the unplated contacts corrode. If you're sure there's a problem with the contacts (i.e. there's a resistance from one side to the other of them) and contact cleaner doesn't cure it, slightly twisting the male part of the contact can sometimes give the mating surfaces better contact.

EDIT: Have you tried new good quality branded bulbs? The filament resistance of poor quality bulbs can vary.
 
Last edited:
Measuring resistances is nowhere near as good a test as measuring voltage drop with the component actually working.

Check the VOLTAGE as explained earlier between the light cluster earth and a good earth point on the car with the component working. Anything above 0.5v and there's a problem. If it's below 0.5v then the earth line is fine and it's time to move on
 
Last edited:

Well on Sunday after going through all of the checks previously mentioned and dismantling the BC and spraying the sockets with contact cleaner the damn warning triangle was still there, so I gave it a rest.

Come Tuesday evening I started up the car to go out for the weekly pub visit and 'Hey Presto' no warning triangle! I have no idea what has caused it, I am just please it has disappeared.

Thanks again to Deckchair and Davren for their advice - until the next time :)
 

Well on Sunday after going through all of the checks previously mentioned and dismantling the BC and spraying the sockets with contact cleaner the damn warning triangle was still there, so I gave it a rest.

Come Tuesday evening I started up the car to go out for the weekly pub visit and 'Hey Presto' no warning triangle! I have no idea what has caused it, I am just please it has disappeared.

Thanks again to Deckchair and Davren for their advice - until the next time :)

Once you've cleared the reason for the error message, it can take three or four 'clean' starts before it disappears.
 

Guess what. First rainfall since the 'Brake Light Fail' triangle went out and it's back again. Perhaps I shall just stick a little piece of insulating tape over the light and ignore it. It will go away when the weather gets warmer.

Oh the joys of owning a Stilo!
 
i just read though your post, if you have this warning then your cruise control wont be working if you retrofitted it,
now i know from experiance that the jtd has a lead missing, when i connected up the cruise control first time i had this same warning come up, when i disconnected it - the warning went away.
i ended up putting an extra lead on the other connector next to the cruise control connector block next to the battery.
i will dig up the posts and you can take a look.
 

Thanks for that Roy but I have already wired 12v to A02 on the black connector block.

The Triangle occurs when the humidity is high even though everything is working A-OK
 
Hey peat I had the same problem on my stilo checked all the
Bulbs side inducaters reverse lights the lot but no blown
Bulbs in the end I found the problem it was the back light
Cluster I found that one of the circuit tracks had cracked and that
Caused the bulb failure so I just soldered a bit of wire over the crack

It hasn't let me down since hope it might help
 

Thanks for the "circuit board crack" suggestion which I will check if a solution from Andy1331 does not solve the problem.

Andy's solution was to wire the earth point to the rear strut mount from the input side if the multi-earth box c30/31 on the inner rear wing. I intend to give it a go later if SWMBO allows!
 
Further to the above; I did wire an additional earth from the rear light clusters to the chassis and I'm sorry to report that it made not the slightest difference!

All last summer the light was extinguished but come the damp cool of autumn it re-appeared and has been on throughout the winter months except for a day in January that was warm and the car had been on a run.

I shall continue the investigation when the outside temp climbs a little higher. My feeling is that it's to do with the body computer, although I have absolutely no evidence of this.
 
  • Like
Reactions: saw
i have this problem too I'm thinking bulb holder now. only managed 30 mile trip and dash warning light/bulb failure,when i get chance im looking at this before thinking about ANY computer
 
I wrote about this a little while ago when I suddenly realised - from reading the failure messages in the handbook - that 'Brake lamp fail' doesn't refer to the brake light bulbs in the rear light clusters. It refers to the low fluid warning lamp in the instrument panel.

Like the ABS Warning Lamp Fail message, this is a warning that the warning light is faulty :rolleyes:

Note, this thread https://www.fiatforum.com/stilo/247321-brake-lamp-failure.html proves that "Brake lamp" is different to "Stop light" - there is also no indication of left or right. I see I'm also not the first person to spot the Warning Lamp Fail messages (vladof did as well).

The brake failure lamp (that's supposedly failed) is likely to be an LED, so probably isn't the problem - which leaves the fluid level sensor or its wiring and connections.

-Alex
 
Last edited:
Thank you for the above Alex but now the question that trips my lips is "Which/what fluid level sensor would that be?
It is not the brake/clutch fluid level sensor as I have checked and it is functional.


 
Back
Top