Warning Light On problems of the 2009 Acura MDX

I have a recurring problem with my air bag system on my 2009 Acura Mdx (vehicle no 2hnyd28249h501436) which my local dealer has been unable to resolve. I first noticed the problem when the vehicle had approximately 21,000 miles. I contacted the service department at kearny mesa Acura and informed them the check air bag light was coming on. Kearny mesa Acura asked if it was on all of the time. I explained that the warning light was on intermittently (some days it was on and some days it was off). They said not to bring the car in until it is just on all of the time (everyday). Several months later it had degraded to the point where the light was on every day, so I brought the vehicle in for service. They tested the vehicle and replaced apart on the driver¿s side airbag (part no 78055-stx-a10). This was at 23,978 miles (on 11/9/2010). Within 6 months to a year, the light came on again. Again, I was informed to wait until the light stayed on consistently (everyday). Once that occurred, I brought the car in again. Kearny mesa again tested the vehicle and replaced the same part (part no 78055-stx-a10). This was at 46,511 miles (on 8/2/2012). Once again, within about 6 months to a year, the light came on. To this day, the problem has not been resolved and Acura wants to charge me $130 diagnosis plus repairs. I feel this is not acceptable on several levels. First of all, this is a recurring problem which began while the car was under warranty (and very early in the life of the vehicle). Secondly, it appears kearny mesa Acura is not properly diagnosing/repairing the problem. It is possible that another component is causing the failure of the part which is being repeatedly replaced (possibly wiring etc). I've also tried writing to Acura directly - president of Honda north America. They said I would just have to pay for any diagnosis or repairs myself.