Is there any way to determine if a relay is bad w/ out replacing it?

My buddy's fan's aren't turning on, even when run in the red. I'm talking about the square-shaped relays under the hood that control the fan.

Any help appreciated fellas!

 

Any help fellas? The Dumbass is out stranded somewhere.....

 

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kinda hard to fix it with car stranded. tell him to unplug the coolant temp sensor at the water pump. this should automatically turn on the fan relays, just to get him home.

 

Yeah, swap it with the fog light relay and see if it works. Those relays don't go bad very often.