Guys, I've had a problem with my locks since day I got car. I've lived with it & would've continued to do so, except now it's worsened. Until today, if I locked driver's door, trunk and gas flap would lock also. Of course all other doors had to be manually pushed down as only driver door and trunk/gas flap would lock automatically. Now, when I lock drivers door, trunk/flap remain unlocked. WORSE is the fact that I can't seem to LOCK the trunk EVEN WITH THE KEY. It seems it SHOULD LOCK with the key. Right now...I just want my trunk to LOCK, will worry about rest later. Thanks in advance for help!!!

85 300SD, Astral Silver
226k miles