2005 Tacoma, the temperature and compass display went blank a few days ago. Searched the forum, found the comments about the 510 resistor and planned on working on it when the weather warmed up.

A couple days later the thing started working again and has worked now for a week without blinking.

Obviously the 510 resistor didn't resolder itself. Suppose the problem was something else, or should I expect it to fail again? Any arcing I should be worried about being generated at the bogus connection?

Obviously the 510 resistor didn't resolder itself.
You sure about that? I've had it happen to the key/ignition unit on the steering column in an older car once. The car would drive fine and then suddenly would just quit running on the freeway. Later on after it cooled, it would run again. Turned out the key unit was worn out from the previous owner's heavy key chain. When it would warm up, the bad connection would heat up the solder and melt it causing a loss of the electrical connection. Then when it would cool, the solder would re-solidify in such a way that it worked again. Happened several times before it lost its connection for good. But it just goes to show that it can happen. Maybe you got lucky and it did this same thing but re-solidifying in such a way that it fixed the connection for good.

I had the same issue and I took it apart to find a cold solder joint. I repaired the solder joints on both resistors and it has been working fine ever since. I would say that it's going to go bad on you so if you have the time just take it apart and take care of it. It's a known issue, good luck.

You guys are right! It went blank again yesterday.

After one of the longest and coldest winters on record, it's supposed to warm up next week, so maybe I can tackle it then.

Its a common problem and you can search over at TacomaWorld.com for the fix. They have a how to posted.