1994 chevy 1500 ext.cab every time i turn the key on and start the truck a tapping sound starts and taps for 30 secs. also when i turn off the truck the same thing happens.the sound is near the heater box under the dashboard.
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It sounds like either you have some debris in the blower motor fan, or the blower motor going bad. That or a lifter in the motor could cause a ticking noise.