Reverse switch Abarth 595

hi there, have an abarth 595 with a plug and play connected emu black. The reverse lights are activated when the reverse gear is activated, as its a mechanical switch however the can signal is not working, the switch has a 12v Switched live as measured with a volt meter, the other wire perhaps is a signal however when connected to the voltmeter there is no voltage reading, most probably its the earth, can anyone assist please if that earth switch needs to be wired to the emu plug and what parameters should I activate? The can system is activated at the moment to FIAT Euro 6.

Thank you!

Something I forgot to suggest when we were talking on the FB group is,

When testing if it works when grounded, you may want to hold off on actually modifying any wiring yet. It’s possible it needs to be setup as high side 12V switching for the euro car, for another purpose.

I’d try just grounding the signal wire to the EMUs switch inputs to the chassis somewhere and seeing if it successfully triggers the reverse lights and parking sensors.

Hey there, so when energized the second wire energizes to 12V. Burnt a fuse 7.5 amps when I grounded it obviously which then led me to get my trusty volt meter out and check the readings. How can I wire it through 12v?

Hello everyone, this issue has been sorted.

I suppose I should chime in here in case anyone else runs into this issue in the future.

Essentially, the issue is that the reverse switch circuit on the newer 500s (confirmed on my US spec Abarth 500, and OPs euro 595) is switched to 12V when reverse is engaged, but the EMU Switch inputs work by being pulled to ground to trigger. On the US spec cars, disconnecting the feed side of the reverse switch from IGN 12V and connecting it to ground is a suitable solution as nothing else is on the circuit. On the european cars it seems that is not the case, and instead a relay (or some solid state arrangement) must be used to bridge the EMU Switch 1 Pin to ground whenever reverse is engaged (and the reverse switch circuit goes high/12V).

When “Fiat 500” or “Fiat 500 Euro 6” is selected on the EMU CAN Dashboard, it sets it so that the EMU’s Switch 1 input is used to send the reverse signal over CAN when activated, which is needed to activate the ESP/ABS/Hill Start’s reverse mode, and the parking sensors.

Hope this helps someone!