Toyota Repair: Fan

Question
Hi, I have a 2013 Toyota highlander V6. The past week, the fan will kick on after the engine is turned off draining the battery.  Have had to jump it about 5 times.  It ony does this sporadically, no pattern to it.  Took it to dealership and they can't replicate the problem or find any problem codes.  They said the battery and alternaterare charging fine. I think they should change out the fan relay or fan assembly all together but won't.  
Any suggestions?

Thanks

Answer
I assume it's still under the warranty that's why they say they can't find the problem, it seems to me it would be easy to duplicate, try going to another dealer that is more committed to customer satisfaction. I personally have not experienced this very same condition so I have no answer for you as to what needs to be replaced.