Can't find cooling fan relay on 2002 Grand Cherokee 6cyl.

It lives under the right headlamp below the plastic bracket that holds the headlamp assembly. You can gain access one of two ways. Remove the bumper fascia, headlamps, and bracket that runs across the front of the car. Or, remove the right headlamp and use a hole saw to drill a one and a half to two inch hole in the bottom of the bracket. Once the headlamp is back in place the hole won't show and the integrity of the bracket will remain.