Code would clear, then reset shortly--car seemed to be running fine. Since I was going out of town for a couple of weeks, took it to the shop. After I described the symptoms, they agreed with you that the PNP switch was the most likely culprit. They also informed me that the ABS module should probably be replaced--- this had been evident for a couple of years now (ABS and TRAC light on intermittently Found a tech (not in that shop) who figured out how to redo the module, and had shop put that in for me.

All appears well now, though I miss the dash lighting up from time to time.