Mystery deepens... Check engine light came on. And the seat warmer worked for a full day. Dealer cleared the code and the seat quit working. Code was for an O2 sensor. Then the AC which had been frosty cold suddenly quite working. Blower worked...but no cool air. Not hot..just not cool. Back to the dealer. A "control head" was determined to be the problem. But. The new CH only got the drivers side to work untill it was "reprogrammed".
Control Heads...Control Modules...out of curiosity, how many of these things are lurking in a 2004 truck? Could it be that all of these "controllers" are failing? cts