B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 230
Aircraft Equipment Problem Less Severe
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action
Aircraft
On taxi out; we observed the LE Flap Transit light illuminate with different slat lights come on; number 8 was the most frequent. I called Dispatch/Maintenance Control; who instructed me to extend them all the way out and retract them; which I did. We had all good indications; so Maintenance said we were good to go. On takeoff roll at 80 knots; we got a Takeoff Warning horn and a LE Flaps Transit light. I rejected the takeoff and returned to the gate after the First Officer calculated the brake cooling data; which was said we were good to return to the gate. Other considerations in the decision were thunderstorms all the way to our destination.The Mechanic said there was water in the control box that was causing a short; which lead to the malfunction.
As we were rolling down the runway on takeoff; at 79-80 knots; we got a Takeoff Warning horn and a LE Flap Transit light. The Captain; PF; aborted the takeoff by 85 knots or so. The RTO didn't engage and we had no other issues on the abort. I think I may have missed the extended and deployed call though. We informed Tower of the abort and exited the runway. We then ran the brake cooling and didn't require any cooling time. After that; we taxied in to the gate and had Maintenance meet the aircraft with no other issues.Maintenance found water pooling under the electrical box due to a clogged drain line and said the box was probably shorting out.
B737 flight crew reported rejecting the takeoff when they received a leading edge flap warning light at about 80 knots.