Lately I have had a few problems with my power. The first thing is I have a back door that will not lock with power - you have lock it manually. 2)When I closing 2 windows at a time they drag now (I never had that problem before). When I have to put on both the heat and the lights - there is a definated power drag. The only work other than recent with the rotors and brakes was alignments and oil changes. I am trying to do some preventative things. Is there anything I might be missing. Advise, please.