I have a problem with non working third brake light. Message appear in dashboard "- check brake lights and also another one that boot is open. After some investigation i found that some one make a mess with wires and for third light there is no wire at all! I use elearn I found correct wire (CN - orange/black) going to pin 18 of Body computer. Someone connect this wire to boot lock motor pin3. I disconnect from boot motor lock and make some test connecting 18w bulb to this wire and earth press pedal but light is not working. It is obvious that body computer is damaged! Is there a chance to disable this message - dtc off (and get a wire signal from left brake to third brake light) because everything is working ok except this 2 warning messages - aditional brake light and trunk open.
Technical Grande Punto aditional brake light not working
- Thread starter makadam
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Technical Grande Punto aditional brake light not working
Hi,
Welcome to Fiat Forum.
Unfortunatly the previous poor repair has almost certainly damaged the Body Computer (BC). It is not possible to disable the warning messages. You will have to replace the BC. Make sure the wiring is correct before fitting the new one or it could be damaged too. There is an issue that the BC is part of the immobiliser system and must be coded to the units in the car. This means fitting a full matching set of used units and keys from another car or a new BC supplied by Fiat prepared for your car. I priced a BC for my Croma in the UK and it was not that expensive. A new BC is easier and less work than the alternative of replacing BC ECU keys etc. The cost may be less than the full set of used parts. Another possibility is an ECU repair company but I not sure how practical that is for you.
Here in the UK a warning light on is a fail on the annual safety test (MOT), unless you can convince the tester that it's just the light that is faulty and it's not a critical warning. I don't know the rules were you are.
Robert G8RPI.
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Hi,
If you have surface mount skills then you may be able to fix the BC. I fixed the BC on my Croma which is very similar. That was a fuel gauge fault not lights. The lights are probably easier. I bought a used BC for parts. The SM semiconductors for the fuel guage were not part number identifiable. I have the remains of the Croma BC which probably has the same light drivers. There is no circuit diagram so you will have to trace from the external connector pin for the brake light to find whic part has failled. If I recall correctly the light driveres ar a IC and each drives 4 lights.
You cannot easily swap the idenity over from 1 BC to another. It's in a secure memory area of the processor IC. It's not in a separate EEPROM. The IC is in a high density BGA package. This is very hard to swap out particuarly because of the mix of very small devices and large power devices close to it.
I have to go out now but could send photos of the Croma BC if you want.
Robert G8RPI.
