Mercury Grand Marquis 2006

means you don't know what is it really and i can't repair it by my self ??

Listen to Jim's advice friend. The Haynes manual repeats 100 times to disconnect the battery when working on anything to do with the air bag system, although I wouldn't know how you are supposed to test it without electric power. There is a procedure spelled out using an Ohm meter, but I would keep hands off the airbag system. Disconnect the whole thing would be my advice.

Try looking at all the plugs underneath your seat, I had an airbag light after I put in my weather tech mats and when I started the car the next time, the airbag light came on and there was a wire unplugged under the drivers seat.

i try my best to do every signal thing but now i think i have to take it to any good car mechanic to solve it .

Once the negative battery cable is removed and all stored power drained from the capacitor, then disconnect every airbag. Now you can test each pins resistance or volts (depending which pin). Whichever pin doesn't read what it should can be dealt with independently. Then unhook negative again, drain capacitor, rehook up airbags. Done.