It was cool today for the first time in a while and I think the heater came on.  It seemed to be delivering warm air but the upper led panel that shows temperatures started flashing on and off.  I turned off all the auto stuff but it kept flashing until the car was turned off.  When it was restarted later it was warm and it did not flash and when auto was turned on the air kicked in.  Is the heater control valve going bad?  This 2004 S Type has 59,000 miles on it.

Found a thread from 2006 on this subject and that time it was a weak battery.  I let the car sit for some time once before and that time the air bag light came on until it had been driven for some time.  This time the car has not been sitting too long but has only seen short trips around town.  So I'm guessing it is a weak battery. 

The upper panel has a chip right next to the on/off button. Given time the soldered pins will fail due to board flex, causing this. Remove air-con controller and resolder chip that should do it.