AF 990 Powers down intermittently?

[TCcamper]

Well, I have a weird one boys and girls! I have had this problem and it is happening more often now. I will be doing my camping thing when all of a sudden the 12volt system just shuts off and all power is gone! It started a couple years ago, but it has been happening more frequently in recent weeks. Now it seems to happen a couple times a week. I was under the sink when it happened the other day, and after about 5 minutes with NO power, I heard a loud CLICK and then the power comes on. I think it might be the 5100 series automatic transfer relay by Progressive Dynamics box that is under the sink. I also found a little black device that had power wires hooked to it, but the connectors were loose, so that be the issue also. I don't know what this device is. So, I was wondering if anyone else has had this problem and what they may know about it?

[TCcamper]

Well, I have come to the conclusion that it WAS the loose connections causing the issue. I have been trying to replicate the failure since I fixed the loose wires, and no problems found. I also noticed that when I turned on my generator, the battery voltage ramped up immediately as it is supposed to. I will be continue my testing in the upcoming summer season, and hope I am correct in my assumption.
Thanks for the replies folks! I appreciate your expert opinions!

[Gripnriprod]

Sure sounds like loose connections. The heat generated will cause the connection to grow worse over time thus heat up and trip the protective device more and more frequently. Apparently it uses a thermal switch that automatically resets once it is cooled down. Don't just tighten the connections as the connectors are likely corroded and may not make good contact. Loosen and inspect them. If there is any sign of corrosion, replace the connectors. If the connection points on the device are corroded, you should consider replacing the device.

[Bedlam]

The transfer relay is for AC power between on board genset and external hookups. I think your master disconnect switch is failing or the wires to it are loose.