Hi everyone, my name is Ron and I'm new to this forum.
A few weeks ago I bought a 2002 Cadillac STS. No general complaints so far except for the fact that 2 days ago it started to make a weird fast paced clicking sound.
It's coming from somehwere under the dash at passenger side, close to the center, left of the fan location.
It sounds like a micro relay is clicking fast and irregularly. When I start to drive, it takes about 10 minutes before the clicking starts. It clicks when driving or idling, even when the ignition is on and the engine is not running.
When the engine cools down a little, the sound is gone.
I tried to remove a few things hoping I would be able to get access to whatever is causing that sound but it seems I have to take half the car apart to get there.
Does anyone have had the same problem?

I have same problem too, I thought that Iam only one.

Sound doesnt hear everytime, I think that sound depend what is air pressure in and out.

You're not the only one.
I'm not sure what's causing this. I monitored it closely and after I start driving it takes about 15 to 20 minutes and then it starts.
If I turn off the ignition switch it's gone. I turn it on even without the engine running and it starts again for about 5 minutes and stops.
I listened closely to where I thought it was coming from and it seems like I can hear fluid or something, moving through tubes.
A few days ago I got the impression that if I hit the brakes firmly, it stops too. When the decelaration is gone, it starts again.

Sofar it's a mistery to me.