Summer coolers fail in three places: the fan motor, the water pump, and the swing. A cooler that blows hot air with a full tank is usually the pump, not the fan.
Bring a small cooler to the shop, or WhatsApp a photo if it is a tall cooler that has to stay in the room. Same number as the fan and mixer work.
Before peak summer in Bangalore the queue is the pump and the swing, not a new cooler. If the fan only hums, that is motor work of the same kind as a ceiling fan, and it can be done at the Kumaraswamy Layout shop.