Hi all, I don't think my evaporator fans are working on my 1999 4.0. Does anyone know how to test them? It's getting hot in Arizona.

 

Have you checked to see if they are running, do the fans spin freely? You can test them with a test probe to make sure they are getting power, check the fuse and relays. You can also hot wire them to see if they will come on.
They are activated thru the ECU from signals from the high pressure switch on your a.c and also from the engine temp switch.
I wouldn't drive it, much less use your a/c untill you get this resolved, don't want to overheat that engine.
Mike