I guess you mean the heater fan keeps going off and on, the fault is the blower motor resistor pack or its connector. If its the connector you will probably need an auto electrician to replace the connector, if its the only resistor pack you might be able to replace it yourself or get an amateur to do it.
Being intermittent my bet is on the connector but you might need to replace both depending on how much heat damage there is (it melts).
Please don't go to a main dealer for a price, its dangerous.
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