Pick the closest symptom. Each answer gives the likely cause, the checks that are safe from inside the house or the ground, and when to stop. Answers marked Stop mean switch the cooler off first; nothing here asks you onto the roof, into the cabinet or near wiring.
Pick a symptom
Safe checks, then a clear stop
Safety first. Roof work, the inside of the cooler cabinet and anything electrical are jobs for a cooler technician. Every check on this site is done from inside the house or standing on the ground. Nothing here asks you to climb a ladder, open the cabinet or touch wiring. If you see smoke, sparking or fire, get everyone out and call 911.
Pick what the cooler is doing. The answer shows here.
Safe checks first
Blowing air, but not cool
Usually dry pads, a stalled pump, a closed-up house or humid weather
Look at the weather first. On humid or stormy days any evaporative cooler cools less. That is how evaporation works, not a fault.
Open a window or two, ideally on the far side of the house from the cooler. A closed house gives the air nowhere to go and starts to feel muggy.
Make sure the control is set to cool, not fan-only or vent.
After about ten minutes on cool, feel the air at a vent. Still warm and dry on a dry day points to pads that are not getting wet.
Next: If the air stays warm with windows open on a dry day, the pump, water supply, float or pads need a look. That is roof or cabinet work, so send a request.
Make sure the control is set to cool. On fan-only or vent the pump does not run.
If you already know where the cooler water shutoff is, and you can reach it from inside the house or from the ground, check that it is open. If you do not know, do not go looking on the roof.
Think back: was the water line shut off for winter and never turned back on? That is common after a fall shutdown.
Next: A pump, float valve or clogged water line is cabinet or roof work. Send a request and say whether the cooler was started up this year.
Switch the cooler off and keep water off your ceiling
Switch the cooler off at its control.
If you already know where the cooler water shutoff is, and you can reach it from inside the house or from the ground, close it. If you do not know, do not go looking on the roof.
Move things out from under the drip and catch the water with a bucket or towels.
A sagging or bulging ceiling can be holding water. Keep people out from under it.
Next: This is roof and cabinet work. Send a request marked urgent with a photo of the ceiling taken from inside.
Switch the cooler off at its control. A squeal is often a belt; grinding or banging can be a bearing, the blower or a loose part. Running it can make any of them worse.
Note when the noise started and whether it changes with fan speed. That helps whoever looks at it.
Next: Belts, bearings and blowers are inside the cabinet. Send a request and describe the sound.
Open more windows. Evaporative coolers add moisture to the air, and that moisture has to leave with the air.
On humid days, switch to fan-only or vent, or turn the cooler off for the evening.
If the house is clammy on dry days with windows open, note it in your request.
Next: Clammy air on dry days can mean the airflow or water balance is off. If humid days bother you a lot, the comparison with refrigerated air may help.
Water running off the roof or down the wall nonstop
Switch it off. A float or drain is likely stuck
Switch the cooler off at its control.
If you already know where the cooler water shutoff is, and you can reach it from inside the house or from the ground, close it. If you do not know, do not go looking on the roof.
From the ground, take a photo of where the water is running if you safely can.
Next: A stuck float or open drain wastes water and can damage the roof or wall. Send a request.