Forgive me if this is dumb. The red protection led came on no my sax 100.4 this morning. I tested the speakers and the right front reads 4.3 ohms the left front reads 5.5 ohms and both bak read 4.2 ohms. I know a speaker short can cause the protection to come on. Is the 5.5 a short or would it read OL on the meter? I the the power, ground, remote, speaker and RCA's and let it sit awhile. I hooked everything back up and it still is in protection. When I turn on the deck the power LED flashed and then it turns to the protection and the power LED goes out. The thing that concerns me is the one speaker at 5.5 ohms, but it is still in protection with all the speakers and RCA's unhooked so now I'm not sure that the one speaker at 5.5 ohms is the bad guy. All the power and ground connections are solid and flowing power. I think that about covers it, let me know if you can think of anything else I can do to try to narrow down the problem.