[rwmj]

One of the issues with the LM was getting rid of heat from the electronics. The Aft Equipment Bay was mounted external to the LM[1], and had to use active cooling (some sort of sublimation system according to [2]).

[1] http://www.hq.nasa.gov/alsj/LM04_Lunar_Module_ppLV1-17.pdf

[2] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1972001...