1/4 CEL JUST CAME ON

the 1/4 CEL just came on last week but went away. This week it came on and stayed. Having read the threads on this issue I removed the cover behind the passenger seat to "pull the codes". No button. I know that I can and will order the test wire and button but I could not find where this should be connected to. There is a small capped off wire that comes off of one of the large wire bundles. Is this where the test wire is connected?

Most of my difficulties so far seem to be electrical contact problems. My garage is a bit damp so that makes things even worse. With the CEL light on, I experience no difficulty starting, no loss of power, I don't think it idles any differently, and lastly, the cats don't seem any hotter than usual. They were certainly not red hot and the crackling sound from the hot exhaust system went away in about 15 minutes, normal I think for a 90 degree day. The passenger side was not any hotter than the drivers side either.

If bad contacts are the problem here too, is it worthwhile cleaning the cat ecu, o2, and thermocouple (don't know what/where this is) contacts and then clear the codes afterwards to see if they reappear? Or is this not a good idea?

Any and all advise is greatly appreciated as always.

 

Thanks Drew, Think I am going to spend some time this weekend cleaning contacts and swapping parts. Should I then clear the codes after changing each part in order to isolate the problem? Or should I just wait to receive the test wire and button?
john