1998 ssei

What is it that is making a fast clicking sound in the back under the car every time i turn my key to on?? It last for maybe 5 minutes or so then goes off...Not a clue !! THANKS

Maybe the levelride compressor for the rear air shocks?

thanks for that answer now where would that be located?

On my 2003 Buick it is under the r/r body behind the wheel well, may be in the r/r corner of your trunk.

if its not the ride controll check the power antenna?