92 400SE Climate Control/Electrical

I've just had a peculiar problem with my CC/electrical system on start up and I'm hoping others have had similar and may be able to narrow the focus of the problem.

Car: 1992 400SE BTB Maint 130K

Problem:
On start up after work [car had been sitting 8 hrs] ambient temp about 72. The deproster went on and there seemed to be no power at the CC control panel. No lights on the entire panel. [generally, the "OFF" light is lit even if the system is not operating] Reselected park, turned the car off, turned it back on and the same problem persisted. I hit one of the buttons on the upper dash vent [the red/blue ones] and the defroster shut off and the system returned to normal operation. Drove the car about 80 miles with no further problem.

Next morning, no problem drove the car 80 miles

Next afternoon it get even more peculiar. The Depfoster activated on start up and when I switched my headlights, the fan speed increased. Swithched the lights off, fan speed decreased. [fog lights, front or rear affected no change] the Vent witches on the upper dash had no effect this time. Turned the car off, turned it back on about 3 times and the system returned to normal operation. Drove 80 miles

This morning, normal operation. did not use the system during driving. drove 80 miles.

If anyone can shed some light on this, I would be very appreciative.

An Update on the problem.

For the past three days, I have shut the car off with the climate control operating in the "auto" mode and upon restart [either after work or the next morning] the system has reactivated in the same mode it was shut down in. Now, I'm scared to shut the thing off, so, I'm forever fiddling with the temp controls!!

If anyone can shed any light, I would appreciate it. I have searched the archives for my car model and "climate control" but have come up empty. If this has been discussed and someone could point me to the appropriate archive, please do!

Thanks