I have a 2008 Ford ranger 4x4. When I start it, the airbag light comes on and stays on along with one single beep. What's the problem? What is faulty?

Both answers are good but jeff's is the technical and proper way to get the conclusion you need if you have the equipment resources to do it,that being said if you go to an autozone or other parts store or a mechanic that has a code reader that covers srs codes(air bag)you will get the problems cause sometimes because it can be a dirty or loose connector that's causing it or a wire but before you go to get it read try disconnecting the battery cables and then clean the connectors associated with the air bags and the restraint control module these are the front seats under them there are occupant sensors that no if someone is sitting there that's why your seat belt buzzer comes on if not buckled and have the air bag circuit going through them each seat must be checked the air bags themselves have connectors the crash sensors in front and on the side and air bags all of this must be done with the vehicles battery disconnected for 5-10 minutes to be safe otherwise you will deploy an/all air bags and that's not good if your face is right next to it when deployment happens you will be hit at 215mph.and it will bust up your face hands or whatever is there that's to close to it so please pay attention here to this it's very important for your safety ///after completeing the work reconnect the cables use your fob to silence the alarm/horn so you don't stay in theft mode now turn the key from off to on do not crank the engine yet observe all the dash lights they will go out after 3-5 seconds this is a self test mode that happens every time you start the vehicle if the problem is still present the beep will happen and the light will be illuminated and now you can go have it read for codes to get the main cause?this was told to you to try to rule out possible causes that cause this to happen but if the codes are there you'll have a better idea what's wrong ok good luck stephen Both answers are good but jeff's is the technical and proper way to get the conclusion you need if you have the equipment resources to do it,that being said if you go to an autozone or other parts store or a mechanic that has a code reader that covers srs codes(air bag)you will get the problems cause sometimes because it can be a dirty or loose connector that's causing it or a wire but before you go to get it read try disconnecting the battery cables and then clean the connectors associated with the air bags and the restraint control module these are the front seats under them there are occupant sensors that no if someone is sitting there that's why your seat belt buzzer comes on if not buckled and have the air bag circuit going through them each seat must be checked the air bags themselves have connectors the crash sensors in front and on the side and air bags all of this must be done with the vehicles battery disconnected for 5-10 minutes to be safe otherwise you will deploy an/all air bags and that's not good if your face is right next to it when deployment happens you will be hit at 215mph.and it will bust up your face hands or whatever is there that's to close to it so please pay attention here to this it's very important for your safety ///after completeing the work reconnect the cables use your fob to silence the alarm/horn so you don't stay in theft mode now turn the key from off to on do not crank the engine yet observe all the dash lights they will go out after 3-5 seconds this is a self test mode that happens every time you start the vehicle if the problem is still present the beep will happen and the light will be illuminated and now you can go have it read for codes to get the main cause?this was told to you to try to rule out possible causes that cause this to happen but if the codes are there you'll have a better idea what's wrong ok good luck stephen

Also this is for everybody who reads this post DO NOT ALLOW PEOPLE TO PUT THERE FEET UP ON THE DASHBOARD IF THE AIRBAG DEPLOYMENT HAPPENS IT WILL PUSH THERE KNEES INTO THERE FACE AT 215MPH AND THAT WILL CAUSE MULTIPLE BROKEN BONES IN THERE FACE AND SKULL FRACTURES AND TRAUMATIC BRAIN INJURY AND EYE LOSS FROM TRAVELING BROKEN BONES THIS IS NOT A JOKE OR A TALE IT'S REAL STUFF THAT HAPPENS JUST ASK AN ER NURSE ABOUT IT SHE SEE'S ALL REMEMBER THERE'S A GOOD AMOUNT OF DISTANCE BETWEEN YOU AND THE BAG WHEN YOUR BUCKLED UP BUT NOW YOU HAVE CUT THAT DISTANCE DOWN BY 3/4 BECAUSE IT WILL BE YOUR KNEES NOT THE BAG THAT MAKES CONTACT IN ACCIDENTS PEOPLE ARE INJURED FROM BAG DEPLOYMENT ALONE AND THAT BAG STOPS THEM FROM WINDSHIELD CONTACT WITH THE SEAT BELT NOW YOUR GETTING PUNCHED IN THE FACE BY YOUR OWN KNEES OH BOY PLEASE EVERYBODY SPREAD THE WORD AND WARN THOSE THAT YOU SEE DOING THIS IN A CAR OR TRUCK THEY HAVE NO IDEA WHAT'S COMING FROM A CAR ACCIDENT AIRBAG DEPLOYMENT YOUR OWN KNEES CAN KILL YOU Also this is for everybody who reads this post DO NOT ALLOW PEOPLE TO PUT THERE FEET UP ON THE DASHBOARD IF THE AIRBAG DEPLOYMENT HAPPENS IT WILL PUSH THERE KNEES INTO THERE FACE AT 215MPH AND THAT WILL CAUSE MULTIPLE BROKEN BONES IN THERE FACE AND SKULL FRACTURES AND TRAUMATIC BRAIN INJURY AND EYE LOSS FROM TRAVELING BROKEN BONES THIS IS NOT A JOKE OR A TALE IT'S REAL STUFF THAT HAPPENS JUST ASK AN ER NURSE ABOUT IT SHE SEE'S ALL REMEMBER THERE'S A GOOD AMOUNT OF DISTANCE BETWEEN YOU AND THE BAG WHEN YOUR BUCKLED UP BUT NOW YOU HAVE CUT THAT DISTANCE DOWN BY 3/4 BECAUSE IT WILL BE YOUR KNEES NOT THE BAG THAT MAKES CONTACT IN ACCIDENTS PEOPLE ARE INJURED FROM BAG DEPLOYMENT ALONE AND THAT BAG STOPS THEM FROM WINDSHIELD CONTACT WITH THE SEAT BELT NOW YOUR GETTING PUNCHED IN THE FACE BY YOUR OWN KNEES OH BOY PLEASE EVERYBODY SPREAD THE WORD AND WARN THOSE THAT YOU SEE DOING THIS IN A CAR OR TRUCK THEY HAVE NO IDEA WHAT'S COMING FROM A CAR ACCIDENT AIRBAG DEPLOYMENT YOUR OWN KNEES CAN KILL YOU