Jered, are the fans working OK now?
The problem is in your diagnosis....the fans in a Xsara if the twin fan system are the same as for a Peugeot 306, where both fans operate all the time and go to high speed when the car reaches 97*c or the a/c is on.
here's a link to the explanation.
Cheers
cooling fans explained....
http://www.peugeotlogic.com/workshop/base/workshop.htm