Use a test light. You should have power coming in on a larger wire pretty much all the time. You have a signal wire that is only hot when the fan is needed. Turn the ac on. the fan should run anytime it's turned on. if that works, your relay works. As always, check the fuses.
on a 1999 jeep grand cherokee where is the coolant fan relay
The engine computer uses the signal from the coolant temperature sensor to decide when to activate the radiator fan relay.
change the coolant fan relay
The coolant fan relay on a 1988 Chevy Celebrity with 2.8L V6 is on the radiator support bracket behind the right hand headlights.
In the vicinity of the passenger headlight.
bad fan or bad fan relay
The fan relay will be located in the PDB box in the engine compartment. The relay is controlled by the coolant temp sensor and the computer. Hope this helps.
jump power from the battery to the fan directly to see if the fan operates. if not, replace fan. interchange another relay with the fan relay to check the relay. there are usually the exact same relay located in the engine bay.
It is on the fender right beside the coolant reservoir.
Small black box in front of battery
bad relay
It should be in the fuse panel under the hood.