AIRBAG LIGHT flash code 12???

[Slikciv99]

Newbie here. Thanks for the help. My bone stock 08 250 has an airbag light on the dash. It started intermittently a while back. I checked the flash code and found the low input voltage code. It sparked a thought, as my truck was beginning to turn over a little slow so I decided to change both batteries. After I changed the batteries I didn't notice it fixed. On a trip to the stealership I asked them to check it out. $125 bucks later they told me it needed a new SRS brain for another $800. I didn't bite. After a while it started to come on solid with no flashes. If you pull the batteries and reset, it will flash for a while first. Well here I am several months later and still have them same problem. I have checked all fuses and disconnected the batteries for a while too. Any thoughts or does the SRS brain sound legit?