You should have 12VDC VOLTAGE present in those headphone type jacks.
Probably looks similar to this fixture from google search

These type of LIGHT/FAN fixtures that would plug into one of those 12VDC sockets are very popular with POPUP tent bed trailers... The LAMP/FAN fixure would snap onto the tent bed aluminum supports

These are available from ETRAILER-AMAZON- etc...
I never had any good luck with the LIGHT/FAN combo units however - Mine did not last long before the fan quit working... A O2COOL 10-inch AC/DC/D-CELL BATTERY fan is much better WALMART-LOWES-AMAZON

Roy Ken