Running light wiring problem identified

Yesterday we did some trouble-shooting on the Airstream problems -- focusing on why we did not have running lights. With the couch removed and the wiring exposed, it made life a lot simpler -- and having my knowledgeable brother leading the effort was the key.

We had known that the power off the tow vehicle was fine and that we had power to the running lights inside the trailer. However, as Barry had suspected back in Texas, the circuit seemed to die in a little black box under the trailer. Sure enough, when he bypassed the box, there was power to the lights -- and in fact, all the lights were working! So now it is a process of finding a replacement for the fried box. (I fried a lead on the box at some point with all the problems of loose leads in the 7-pin connector).

So here's what I've posted and sent to a couple of potential suppliers:

I have a 1999 Safari and have had trouble with the running lights. I just found out that I fried a breaker or relay that is between the battery and the lights. It is a small black box with four paddle connections -- one for a hot wire, one for ground, and two for the blue trailer light wiring. It says SC-906 on it and is 12v, 30 amp. The connection points are marked 85, 86, 87, and 30.

It's nice to get an answer to this nagging problem -- now to find the part. And here's the answer I just got from the Airstream Forum:

It's a generic auto relay, should be able to find one at any auto parts store. You can see that one of the pins is burnt, with all the black plastic around it. Curious why it would fail but I would get a new one and see what happens.

What a resource the Internet can be. Off to Advance Auto Parts.