Originally Posted by PerfInit

The 737-800’s have had a lot of trim air faults in the early days. There is a Boeing FCOM Bulletin titled “Nuisance Zone Temp Light Illuminations on 737-800 Airplanes.” The procedure is as follows:

After landing, prior to first power transfer:
Trim Air Switch ……………………………………….. OFF
Air Conditioning System ……… ____Pack(s), BLEEDS ON

Prior to takeoff, after last power transfer:
Trim Air Switch ………………………………………….. ON