Generator Battery Vent Fan
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The generator battery vent fan is a serviceable component attached to the rear of the generator battery carrier assembly. This variable speed fan is controlled and powered by the generator battery disconnect control module. The fan draws cooling air through the bottom of the generator battery carrier assembly, exhausting it into the spare tire tub. Fan speed is varied, as required, to ensure that generator battery temperature remains within desired limits.