What was found
AIRCRAFT WAS NOT GROUNDED: DURING PS CHECK FOUND LH/RH FWD AFT EMERGENCY EXIT ROW EXIT MARKERS AND RED SEAT MOUNTED RED EMERGENCY LIGHTS ALL OUT. ALSO RECEIVED R ESPU FAULT DURING IBIT. RH ESPU LOCATED AT EMERGENCY EXITS IS GIVING UNIT FAULT. EPSU IBIT SHOWING UNIT FAULT. R/R EPSU 12WL IAW AMM 33-51-38. DURING OPS CHECK LIGHTS WORKED FOR APPROX 4 SECS AND THEN WENT BACK OUT. AFTER - NEW EPSU SHOWS UNIT FAULT. FOUND SHORTED OUT WIRE GOING TO SEAT MOUNTED EMER LT ON ROW 9ABC. REPLACEDEMER LT HARNESS ON ROW 9ABC IAW CMM 25-40-07. R/R SEAT MOUNTED PARTS.