General Third Brake Light not working

[JackMason]

Hi all , i’ve had a constant issue of my third brake light not working , i’ve replaced the unit as a whole with a led one , the wiring in the boot loom was all knackered and i fixed that and is all fine now but it still isn’t working and is giving me a warning light aswell , does anyone know what could be causing this and what the fix is ?

 

[Sylvester22]

Could be wiring issue, also led light instead of regulator ones, can also cause issues.
Needs a scan to see what's the warning light is about.

 

[JackMason]

Could be wiring issue, also led light instead of regulator ones, can also cause issues.
Needs a scan to see what's the warning light is about.

I’ve only got a cheap obd reader and the ones i’ve seen for fiat either require a laptop or are like £500 , any reccomendations ?

 

[Sylvester22]

I’ve only got a cheap obd reader and the ones i’ve seen for fiat either require a laptop or are like £500 , any reccomendations ?

Fiat and Italian cars don't communicate well with handheld devices, so a laptop is necessary, but then a £60 programm and a few cables for £15-20 from ebay, and you'll have a scanner, that's still much better deal than being changed £50-70 for only 1 scan.

 

[Greasytrucker]

Hi all , i’ve had a constant issue of my third brake light not working , i’ve replaced the unit as a whole with a led one , the wiring in the boot loom was all knackered and i fixed that and is all fine now but it still isn’t working and is giving me a warning light aswell , does anyone know what could be causing this and what the fix is ?

Is there power to the wires for the third brake light now? If so then you either need to revert back to a conventional 3rd brake light or add a resistor so it knows there’s a light there otherwise the warning light will persist

 

[JackMason]

Is there power to the wires for the third brake light now? If so then you either need to revert back to a conventional 3rd brake light or add a resistor so it knows there’s a light there otherwise the warning light will persist

the issue was there before i replaced the unit , and what wattage and resistance would i need ?

 

[JackMason]

Fiat and Italian cars don't communicate well with handheld devices, so a laptop is necessary, but then a £60 programm and a few cables for £15-20 from ebay, and you'll have a scanner, that's still much better deal than being changed £50-70 for only 1 scan.

well to be fair it won’t probably end up being one scan because i’ve got a few other issues but i’ve seen a lot about the free version of MULTIECUSCAN so i’m going to get the cable for that and give it ago

 

[Sylvester22]

well to be fair it won’t probably end up being one scan because i’ve got a few other issues but i’ve seen a lot about the free version of MULTIECUSCAN so i’m going to get the cable for that and give it ago

Free version didn't work for me much, but the paid version works great. Imo well worth the investment, as a start just get the ELM327 cable, that's the main one, the others for airbag and other bits, check YT there's videos explaining the differences.

 

[Greasytrucker]

the issue was there before i replaced the unit , and what wattage and resistance would i need ?

So there is power going to the wires for the third brake light if tested with a multimeter?

 

[JackMason]

So there is power going to the wires for the third brake light if tested with a multimeter?

No there isn’t but the wiring seems fine in the loom in the boot because i’ve just fixed it

 

[Greasytrucker]

Is it a bulb warning light that’s illuminated?