I just bought a 04 Deville and noticed this morning when I went to unlock it the back only unlocked... sometimes the blower doesn't come on. But decided to randomly....when I turn the interior lights on the rear only come on..... when the back only unlocked I unlocked the front with the key...got in and it wouldn't get start. So I got out locked it up again then unlocked it first with my key and then it started. What do you think is going on??