Someone posted a how-to on resoldering the circuit board connectors because of cold solder joints. Last evening, I removed the overdrive control relay (it was tough to find it) and resoldered all the connections on the board. The problem that I had encountered (no overdrive and buzzing sound from behind the dash) is now cured. I found two suspect solder connections, but reflowed the solder on all connections. My heartfelt thanks to whomever originally posted this proceedure. I looked, but could not find the post.