Antitheft system in T&C

I have a 1997 Chrysler Town & Country.....last week the van would start for about 1-2 seconds and then just shut off. I know the engine was getting fuel (able to rev and could hear the fuel pump kick on). After much headache, I called the Chrysler dealership....he asked me to lock my vehicle using the remote and then unlock it with the key manually and try to start - low and behold, it started right up! This morning it did the exact same thing again, but this time, I can not get it out of alarm set mode - even after following the directions in the manual several times....I tried for 20 minutes. I called the dealership again and said that there must be something in the computer/sensor or something that is causing it to stay stuck. The dealership said it could possibly be the body control module, but he was not sure. He said that really all I could do was have it towed into them, hooked up to their computer and have it diagnosed. I asked if they could do a service call; of course the answer was no. You see, my father is a mechanic and I was hoping to purchase the part and just have him install it. Of course, the dealership does not want me to do that. My question is, is there any other part other than the body control module that would cause this to happen?