Problem airbag ecu Fiat Panda

I have a panda of 2010 in the workshop and has had a head-on collision that ruined the muzzle in a way that is not serious and does not blow up the airbag. The fact is that by then the body, and therefore the diagnosis, it does not detect ir? the airbag control unit, and thinking that was the route I bought another used, with the same problem, of course, giving me the anomaly airbag in the dashboard.

I checked all the fuses and are ok, on to the unit I have a cable voltage of 12v and one that you, and not get to 4-5 volts under lock and key. To someone ? happened to you?? It could be that the body computer in shock, when he tried to open the airbags, has had a break on the power line that goes to the ecu the same?? Possible solutions??

With skema electric hand control power supplies and then go in diagnosis in the node drivers