Heater blows hot air but then slowly dies. After
being turned off for a bit it starts up again but dies
15-20 seconds later.
This sounds like a case where the vehicle may have poor circulation in the cooling system or at least to the heater core. After turning on the heat and the heater core (coil) blows down, the heat is stripped from the coil. Turning the heat off allows the coil to be replenished with hot water allowing more heat the next time it is turned on. Playing this sequence through in my head makes sense that you may have a circulation issue. I would highly recommend to have the cooling system inspected and flushed if necessary. The heater core itself could be plugged up, or the coolant may simply be low.
It is still has hot air but sounds if the blower has come to a stop. Is it the blower then or is there something else that may be the issue
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