Sometimes when I start the car and then turn on the climate control, I hear a clicking noise. I turn it off and try after a few min. which is then quiet. Also, recently, the blower motor will sometimes not work. I try later and all is well. Should I just replace the blower motor. It's about time for a new blower motor according to past history. Seems that they last about 90,000 miles. But, what causes the clicking noise?

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Paul 1987 300 SDL; 2000 ML; '69 MGB; '68 VW Fastback