In general, these are the hardest and most frustrating kind of problems to troubleshoot in my experience. That said, you can investigate areas that have both electricity and heat since it seems your problems may be caused by condensation that clears after heat is applied. Unfortunately, since that includes the engine compartment and cabin, that only initially removes the trunk, and even that shouldn't be completely ruled out. Check both of the fuse boxes - I think Eldo has the same set up as STS with one under the hood and one under the back seat. If one box has the radio and sunroof power in it I would suspect that more than the other. Past that I would need to see a wiring diagam to see if there are any modules involved that could be getting a bath.
Does your AC drain normally - will it leave a puddle after its been parked when the AC was running? I'm wondering if maybe the AC drain tube is plugged and not getting the condensation out of the car the way it should. I'm also assuming in both cases you had the car in Defrost to remove condensation from the windshield.
This is a real
Re: Phantom Problem with Sun Roof 
