ACR MLG TKOF ABORTED WHEN SECONDARY DOOR WARNING LIGHT ILLUMINATED DURING INITIAL PHASE OF TKOF PROC.

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BACKGND INFO ON DOOR WARNING LIGHT SYS: THE MLG ACTUALLY HAS 2 PAX ENTRY DOOR WARNING SYS. THE 'STANDARD' MLG COMES WITH AN AMBER LIGHT WHICH ILLUMINATES WHEN THE DOOR IS UNLATCHED; SUCH AS WHEN THE PLANE IS PARKED AT THE JETWAY. MY COMPANY HAS ADDED AN ADDITIONAL SYS WHICH ILLUMINATES A RED PAX DOOR LIGHT WHEN MICROSWITCHES IN THE DOOR AREN'T CONTACTING PROPERLY AND EITHER THROTTLE IS MOVED ABOVE A CERTAIN PWR SETTING. THAT PWR SETTING IS SUCH THAT YOU HAVE TO EXCEED IT JUST TO GET THE AIRPLANE MOVING IF IT IS STOPPED. ON THIS DAY; THAT RED WARNING LIGHT DID NOT ILLUMINATE AS WE TAXIED OUT OF THE GATE. AS WE BEGAN THE TKOF ROLL; THE CAPT ADVANCED THE THROTTLES AND; JUST AS I WAS GETTING THEM 'FINE TUNED;' THE RED DOOR WARNING LIGHT ILLUMINATED. WE HADN'T EVEN MADE IT TO A SPD OF 60 KTS YET. THE CAPT CLOSED THE THROTTLES AND EXITED THE RWY AT THE FIRST AVAILABLE EXIT. I TOLD THE TWR 'WE'RE REJECTING THIS TKOF.' WE PULLED OFF INTO THE RUN-UP BLOCK AREA AT THE END OF THE RWY AND CYCLED THE DOOR ONE TIME. THEN; WHEN THE THROTTLES WERE ADVANCED; THE RED WARNING LIGHT DID NOT ILLUMINATE; SO WE DETERMINED THAT THE DOOR WAS INDEED SAFE. KEEP IN MIND THAT THE OTHER DOOR WARNING (AMBER) NEVER DID ILLUMINATE EXCEPT WHEN WE CYCLED THE DOOR -- AS IT SHOULD. THIS MOST PROBABLY WAS A MICROSWITCH PROB. THE SAFETY OF FLT WAS NEVER IN QUESTION AFTER WE EXITED THE RWY TO INVESTIGATE. THE RED LIGHT DID NOT ILLUMINATE AS WE LEFT THE GATE. THE FLT WAS COMPLETED WITHOUT INCIDENT.