Fiat 500 Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hey all,

so I’ve been replacing my old halogen bulbs in my 2012 Fiat 500 Sport with LEDs (turn signals and brake lights done so far). I had no issue with the turn signals as the lights I got are Canbus ready. However, for my brake lights, I’ve been having issues with getting the car’s computer to stop warning me to “Check stop lamps”. I have some resistors which I did my best to install and wire up correctly using wiring diagrams I found online. These were the only two I could find for the external lights (courtesy of a post on this forum a few years back!) I think I got the left one wired up right, because when I put the LED on that side but kept the halogen on the right, the dashboard had no errors, but I must have messed something up on the right side because my dashboard lights up with the error once I put the LED in. I can barely read what it says for the right tail light wiring, but I thought I read “green/yellow” for RT STP LMP, so I wired the resistor to the black and green/yellow wires, which clearly wasn’t the right move. Anyone have any advice? Did I wire it to the wrong wires?
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #2 ·
Hey to anyone who is interested. I have solved the issue. The wiring diagrams I followed and uploaded here are CORRECT. The splicing clips I used weren’t very sharp and didn’t break through the insulation of the green and yellow wire, which is the positive wire for the right brake light. After pulling it apart, removing a tiny bit of the insulation and replacing, it works perfectly, with no dashboard errors.

If you’re planning to do this to your own 500, the process with the turn signals was as simple as changing a bulb. Plug and play. The brake lights, which were the thorn in my side, would have been just as easy had I bought LEDs that are “Canbus ready”, or in other words have a resistor built into them. The ones I bought didn’t have that, so I had to add one (link to the listing i used) in series with the brake lights. This is a fairly simple process, it just requires you to be able to fit the resistor under the tail light housing, which was fairly easy as well, just took a couple minutes. My car looks awesome now, especially with the crisp on/off of my bright turn signals. Good luck to you when you try this in the future.
 

·
Registered
Joined
·
31 Posts
Did you have to do 1 resistor on each side (ie 2 total for the brake lights)? or was 1 resister for both brake lights enough?
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #4 ·
Did you have to do 1 resistor on each side (ie 2 total for the brake lights)? or was 1 resister for both brake lights enough?
You need one for each. The car’s computer detects voltage for each individual light and expects a certain total for the circuit. If you only put one it’ll throw errors.
 

·
Registered
Joined
·
31 Posts
You need one for each. The car’s computer detects voltage for each individual light and expects a certain total for the circuit. If you only put one it’ll throw errors.
Got it, thanks that makes sense. I wasn't sure if the left/right share the same circuit or were separate.
 

·
Registered
Joined
·
18 Posts
Where do we mount the resistors after connecting them to the brake lights? trying to find space..


Hey to anyone who is interested. I have solved the issue. The wiring diagrams I followed and uploaded here are CORRECT. The splicing clips I used weren’t very sharp and didn’t break through the insulation of the green and yellow wire, which is the positive wire for the right brake light. After pulling it apart, removing a tiny bit of the insulation and replacing, it works perfectly, with no dashboard errors.

If you’re planning to do this to your own 500, the process with the turn signals was as simple as changing a bulb. Plug and play. The brake lights, which were the thorn in my side, would have been just as easy had I bought LEDs that are “Canbus ready”, or in other words have a resistor built into them. The ones I bought didn’t have that, so I had to add one (link to the listing i used) in series with the brake lights. This is a fairly simple process, it just requires you to be able to fit the resistor under the tail light housing, which was fairly easy as well, just took a couple minutes. My car looks awesome now, especially with the crisp on/off of my bright turn signals. Good luck to you when you try this in the future.
 
1 - 11 of 11 Posts
Top