Where do I look for the problem?

99 STS.

Key in recall workssort of. Sometimes have to push the recall button on the dooroccasionally repeatedlyto get everything into the proper position. Not every time and eventually everything is where it's supposed to be.

Troubleshooting info in service manual is of little or no help as it only seems to describe "doesn't work" situations-not works sometimes, and sort of works otherwise.

As I understand operation, a resistance value in sensors is stored and things are moved until it matches. I [think] it's supposed to self-compensate for natural voltage fluctuations like the resistance "ladder" used for the steering wheel switches. Those always seem to work properly, but I rarely use them.

Thanks in advance for any suggestions.