Re the ignition switch issue--that's exactly what produces that problem, and replacing the switch unit itself is adequate; my indie did that, using the same tumbler assy and keeping the same key. Expensive in terms of hours as the cluster has to come out, which means the wheel comes off, which means the airbag comes out, etc. etc. I can tell you that there were no other symptoms to suggest the ignition switch--starting and running were fine, radio didn't go out, lights didn't go out, etc.

Re your problem, Tom--I'm no great expert but it sounds like something electrical has been going intermittent on its way to failing altogether, and the solder joints on the control unit (meaning the one with the buttons and dials) come immediately to mind, as does the potentiometer on the temp control dial--the latter especially if the fan's on but there's no ability to modulate the temperature of the air. My next area after that to consider would be the "brain" unit itself.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)