A FLC ON AN ACR DC9-80 EXPERIENCES A DEV FROM THE AIRWAY WHEN THE PIC IS DISTR BY AN AFT CABIN DOOR WARNING LIGHT. THEY OVERCOME THAT PROB WHILE ATC GIVES THEM A 'HEADS UP' AS TO THEIR POS.

Narrative

WHILE CLBING THROUGH FL250; THE AFT CABIN DOOR CAUTION ILLUMINATED. PER THE ACFT OPS MANUAL VOLUME 1; I CALLED FOR THE QRH CHKLIST FOR AFT CABIN DOOR LIGHT; TO WHICH MY FO ANSWERED 'THERE IS NONE;' AND HE SHOWED ME THE ABSENCE OF THIS ITEM IN OUR QRH. MY FIRST ACTION WAS TO CHK THAT WE WERE MAINTAINING CABIN PRESSURE; WHICH WE WERE. MY MOST RECENT LEGS FROM RNO HAD BEEN TO LAX; AND AS LAX IS ON OUR RTE; I WAS 'SPRING LOADED' FOR J7; EVEN THOUGH UP TO THE DOOR LIGHT I WAS CORRECTLY TRACKING J5. ELECTING TO CONTINUE AS PF; I SET THE FRA 342 DEG RADIAL ON MY SIDE (WHICH IS WHERE THE ERROR OCCURRED); AND HAD MY FO CALL THE LEAD FLT ATTENDANT UP TO GO BACK AND CHK THE DOOR. I INSTRUCTED HER TO VERIFY THAT THE HANDLE WAS FULLY SEATED; AND TO LET US KNOW IF THERE WAS ANY NOISE FROM THE DOOR. ABOUT 2 MINS AFTER SHE WENT BACK; THE LIGHT WENT OUT AND DID NOT REILLUMINATE. AT THIS TIME CTR QUERIED US AS TO OUR ROUTING; WHICH WE WERE NOW APPROX 10 MI W OF. WE ANSWERED J5; AND THE CTLR ADVISED US TO TURN 20 DEGS L AND PROCEED DIRECT LAX. HAVING REALIZED THE MISTAKEN COURSE SETTING; I ASKED THE CTLR IF WE HAD ANY TFC CONFLICT OR OTHER PROB WITH HIM; AND HE SAID NO. WE CONTINUED TO SAN UNEVENTFULLY. THE FACT THAT OUR QRH DOES NOT LIST ANY PROC FOR 'OPEN DOOR' LIGHTS WAS QUITE SURPRISING TO ME; BUT AS I AM CURRENT AND QUALIFIED AS A MECH I COULD DIAGNOSE/FIX THE PROB WITHOUT DIFFICULTY. I BELIEVE I WAS DISTR BY THE FACT THAT SUCH A PROC WAS NOWHERE TO BE FOUND IN OUR CHKLISTS.