How did you check the relay?
I ask this next question because some people look up relay location and relays for a cherokee and not the grand cherokee. And they are different.
Were was the relay located?
Did you hot wire the fan directly to the battery? If so did it come on... If not then most likely you need a coolant fan motor...
Here is a picture of the relay for a Grand Cherokee..
This is the location of the relay....Behind bumper on passenger side
Friday, July 25th, 2008 AT 4:52 PM