Seized caliper?
 

The right front caliper seems to be not fully releasing. It sometimes happens more than others, from one use of the brakes to the next. It can go weeks without acting up, and then... I replaced the caliper and it didn't solve the problem. I'm thinking the ABS modulator may be the culprit. Any ideas?

Rubber brake line
 

My 2007 had same issue. It was the rubber flex brake line. NAPA had them in stock so do both sides.

Replace both front hoses like tomwalt suggested. You didn't say what year your Equinox was, but the front brake hoses commonly fail on 2005-2009 models. They usually collapse and act like a check valve which keeps hydraulic pressure applied to the calipers.

The year is in my sig line- '05. The rubber lines look fine. Wouldn't there be visual evidence?

I have seen blocked brake hoses that looked ok from the outside.

from my experience with the rubber line what happens is the metal bracket that you bolt to the control arm will rust on the inside and will squeeze the hose. found this out when i went to replace the hose and cut apart the old one, didnt see nothing wrong till i got to the bracket and cut it off and you could see the difference in hose size from the bracket squeezing