Clicking Noise From Sv2000 Dvd/vhs What Would Make A Clicking/ Ticking Noise When You Turn On Your Heat Or Air In A Truck?

What would make a clicking/ ticking noise when you turn on your heat or air in a truck? - clicking noise from sv2000 dvd/vhs

I was wondering what you think about making a tick / click noise when I am the heating or air at any speed or configuration. The air is hot and cold out when the heating Mayebi.