Relay noise after changing front pads?

Hi all, I've gone thru the past posts, and it looks like this is a new one.
I changed the pads and rotors on my 2002 Grand Caravan today. A bit of fluid leaked out of the master cylinder tank when I compressed the first caliper (left side). After completing both sides, I started the van and noticed a loud relay click every time I pressed the brake pedal while in Park. In R, N etc the noise goes away. No indicator lights go on with the relay. The van stops fine and the brake fluid level seems fine.
Thanks in advance for your suggetions!

CL16Sailor, just a guess but could it be the shift interlock relay? Maybe not the right name but it keeps the driver from shifting out of park until the brake pedal is pressed.