Maybe someone here can maybe offer some type of explanation for this. I was at KRC and Marty had another truck with a 4.7 with a computer flash. We unplugged my pcm and plugged in the one with the flash just to see if it made any difference. Well my defrost button started flashing and my a/c button (which the a/c was on) went out. The pcm only stayed installed for 5 or 10 minutes. We re-installed my pcm and the problem still persisted. The truck does not turn on the check engine light. We tried disconnecting the battery and everything. So now my light to indicate whether my a/c is on or not does not work (no matter whether the a/c is on or not) and my defrost button constantly flashes and it is driving me crazy :cussing: :help:. Any ideas would be greatly appreciated. No the a/c system is not low on freon we already ruled that out.