As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT PACK LIGHT ILLUMINATED ON PUSH BACK. GROUNDED - YES. ACFT CHECKED AND RELEASED IAW MEL 21-1G. SUPPLIED PNEUMATIC PRESSURE TO BOTH THE LH AND RH PACKS WITH APU. RH PACK LIGHT WAS NOT ILLUMINATED. PERFORMED B737-900 FIM 21-51 TASK 802. DETERMINED DEFECT WAS AN INTERMITTENT FAULT. PRECAUTIONARY PERFORMED ZONE TEMP CONTROLLER BITE TEST REF B737-900 AMM 21-51-00-700-803. GROUND VERIFICATION SUCCESSFUL. NO FAULTS NOTED. THIS CLEARS MEL 21-1G.