The most likely (80%) problem is that one of the gas valve coils is not working. There are two coils on the top of the gas valve. One has three connectors and the other has two. If you have an ohmmeter, you can test them for continuity to find the faulty one. Otherwise, simply replace both of them. They are held down by a couple of screws. Good luck.
poppahess, December 2006
