
I keep a spare of all of the FI components just in case one goes bad and this way if I need it right away I don't have to wait for shipping. You can usually get pretty good deals on these parts from fellow members doing part-outs.
As far as replacing it, there's a good diagnostics for it here:
http://www.wcmotors.com/personal/Fiat%2 ... agnostics/
It's easy to test and if it's working properly there's really no need to replace it.
What I've found is that it's bypassed by a PO not because it failed, but because they were unaware of the inline fuse that supplies one of the 12V sources to it, or they couldn't find the fuse holder behind the main fuse panel.
Ron