2012 FF licence plate lights not working PLEASE HELP

Modern cars are loaded with extremely sensitive electronics, and they don't take kindly to being tinkered with. I think you should abandon the attempt and put the original bulbs back in it. I can't help you with the location of the fuse block, but it's got to be in the owner's manual somewhere.

 

My Portofino's fuse box is totally from the picture in the Owner's Manual. The dealer's Service Manual has the same incorrect picture. Good luck.

 

You,'ve figured out that the led do have a different resistance (ecu do not like it) . Unlike incandescent bulbs, leds are also polarized. Just check that your led bulbs are receiving +/- on their appropriate side.

This being said what' s the point in using low consumption led if you then have to add resistors that will just waste as much energy as the regular bulbs?

 

I don't know about the FF for sure, but most modern Ferrari/Maserati have the low power lights driven directly from the body computer.

 

Usually the number plate lights are on a fuse shared by other lights. Just look for other lights which are not working. e.g. panel/switch backlights, luggage compartment lights, sidelights, etc, and see if there is a corresponding fuse.

Typically, the "body computer" is found in the dash outboard of the steering wheel. Physically, after removing the cover panel, it looks like a relay/fuse panel.

 

Put the stock bulbs back in and see if they work. You may need to do a key on off cycle tho. If they work leave the damn car alone.

 

Finally bear in mind that led are (usually) not 12v so some sort of voltage ma'agement is implemented: either led in series (bad for the overall output), resistor, or voltage regulators that can be noisy.

Cheap leds can be a pain.