After you said this I looked it up (I'm no electronics solder specialist), and it looks like every joint on the board qualified before I touched anything.
After I fixed mine (it was solid all the time), it started acting up again. So I contacted SOA and they said take it to the dealer to verify. I paid for it out of pocket and SOA sent me a check to cover parts/labor. They seemed very interested in getting it resolved quickly. Of course I know it is for the good of Subaru as well, the bad part/fault can cause your airbags to not deploy. But it is still nice to have a company react and "get it done" fast so that you can have peace of mind...not worrying if the damn light was going to stay on when you are miles away from home with your family in the car...
Long story short, if you don't want to depend on your soldering skills to save your life, contact Subaru.