I replaced the tail lights in my 2015 Fiat 500 Abarth with the Euro version. I am using the supplied conventional bulbs. My home made harness adapter and 3d printed center panels worked great and I have no complaints about the Euro Tail lights. As most people know, this Euro tail light doesn't have a provision for a back up light, so I ordered this LED module to use as a back up light.
I 3d printed a nice mounting fixture so I could put it just forward of the center "grill" in the rear diffuser and wired the hot side to the left back up light wire and wired the ground to the chassis. It didn't work, so my first step was to insure I had a good ground. I disconnected the ground and verified that the chassis ground was good. When I touched the ground wire to the chassis, the light came on. However, when I lifted the connector and touched ground again, the light will not come on again. I am not getting any warnings on the instrument panel. If I let it "rest" for 30 seconds or so, the light will illuminate the FIRST time I touch the ground wire to the chassis. But it won't come back on once I interrupt the circuit unless I let it "rest" for a while. Then when I connect the chassis ground again, the light works and stays on as long as the circuit is not interrupted. I tested it for several minutes and it doesn't seem to be an overheating problem nor does the Canbus "reject" the LED module after a while. It just continues to illuminate on the FIRST connection after a "rest period".
I read that the back up light was not part of the Canbus system, but I think that information is wrong.
I have two thoughts. Perhaps the LED module will work if I connect the ground wire to the ground wire associated with the tail light wiring as opposed to simply grounding it to the chassis.
Or, perhaps I need a resistor in the LED back up light circuit, but I have no idea what size is appropriate.
Any thoughts about how to get this module working? I hate to go a different direction since the mount I made was a bit time consuming and is just perfect for this system. But I'll do what is necessary to get a functional reversing light.