Well done.. perseverance Wins the day!

 

The heater is on a low setting as normal as pennywise says. It is only on when the ignition is on though because otherwise the battery would run flat over night wouldn't it

 

Peanut,
Right. What I should have said, to be more clear, is that the noise I heard was only while the engine was running. The fan will come on with the ignition switch in "on," but before the engine has started. That is, the fan will run without the engine running. To get the engine running, one must turn the key to position 3, or "start."

Anyway, the noise was not the fan. It was the booster check valve fluttering due to a vacuum leak, which was ultimately tracked down to a ballast? chamber in the battery compartment. As PennyWise said, perseverance wins.

thanks, all...
-David

 

glad to hear you tracked the cause down at last. I also have a `noise ' I cannot track down yet ,its frustrating isn't it. Its surprising how few 944 owners know about the `always on low' heater fan setting .