What was found
AIRCRAFT WAS GROUNDED: PACK 1 LIGHT ILLUMINATED. MOMENTS LAT ER PACK 2 LIGHT ILLUMINATED AFTER RUNNING QRH PROCEDURE. PACK LIGHTS EXTINGUISHED. A MINUTE OR SO LATER PACK 2 RE-ILLUMINATED. PACK 2 TEMP INCREASED TO 197FTEMP SLOWLY DECREASED TO ~110F PACK 1 TEMP AFTER RESET REMAINED BELOW 80F. DECESION MADE TO RETURN TO DFW,. EMERGENCY DECLARED AND AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED R/H ACM PER AMM 21-51-04.