New battery fitted but passenger airbag light stays on and no radio?

Speculation without further details but 3 usual causes:
1. Clock spring in steering wheel for airbag open circuit.
To Test - disconnect battery-disconnect airbag ribbon from steering wheel -insert 3 -8ohm resistance bypass in airbag plug below steering column feeding clockspring. reconnect battery and see if light goes out after 5 seconds
2. Check passenger seat sensor operational.
To test - with ignition off - disconnect plug under passenger seat for sensor pad and insert test ohm resistance in feed plug. switch ignition on as test 1.
3. Check steering wheel button operation. if any radio actions do not work problem may be infrared link between steering wheel and radio (especially aftermarket modules)

Get the airbag trouble code read and then you'll know what's going on. Without that you've got no starting point.

Are you sure you didn't put the battery in backwards? I don't mean to suggest that you are not intelligent, but we all make mistakes like this from time to time. If it's not that, you may have blown some fuses. Check your manual for which fuses control the radio and passenger airbag and replace them if needed (with the car not running). . .

Could be a problem with the sensor in the seat. The system thinks someone is sitting in the seat and the seat belt is not fastened.

Hey, my mate had the same problem, just in a Mini, he went to a garage and they told him the sensor in the passenger seat was broken, and the entire seat needed to be changed, costing around 2.250$. He searched a little around and found an airbag emulator, that gets your system to think someone is always seated. In case of an accident the airbag will ALWAYS go off, on both driver and passenger seat. He found it on amazon: http://www.amazon.com/gp/aag/main/ref=olp_merch_name_1?ie=UTF8&asin=B00E3C1IPW&isAmazonFulfilled=0&seller=A3VPDTQ49IXC7U - it is a quick fix, but a solid one.

i dought it dose your horn and cruise work if not it is a clock spring

usually passenger air bag can be turned off with a switch just inside the door on the side of the dash, but will probably need resetting on an obd11, other than that a cable under the passenger seat is faulty

the likely fault is the cables running to the seatbelt pre-tensioners under the drivers or passengers seat in the front of the car.

This may be simply the plug and socket have become seperated from sliding the seat back to clean, a common fault, or the airbag "clockspring" connection unit in the steering wheel has a broken ribbon cable inside the column housing.

To see if its the airbag clockspring, buy a 4 ohm resistor from maplin or radio shack, disconnect the battery on the car, unplug the airbag in the steering wheel and connect the resistor across the 2 contacts in place of the airbag, reconnect the battery, if the light goes out the clockspring is the fault, if not its the SRS system wiring under the seats.

Common fault on FORD
Usually due to a poor connection in the YELLOW PLASTIC CONNECTOR underneath the passenger seat.
Just push it together properly and it should clear the AirBag fault