Why does your 1994 Chevy silverado go click click click under dash when starting or after shutting off engine and stop after about two minutes?

Answer 1

I thnk you're hearing the electric fuel pump. The clicking noise comes from the fresh air/ inside air mode activator. There is a compact black actuator on the air box just under the bottom of the glove box. You can stop the noise by disconecting the two wire connector going to it, but you won't be able to use the REC recirculation button for inside air. There is likely a missing tooth on one of the gears inside the unit.