1999 Taurus problem with blower motor

The heater/AC blower on our 1999 Taurus stopped working recently. At first it would work while we were going down the road, but would go off when we stopped for gas and then not come on again when we started the car up agian. If we left the switch in the on positon for a while, it would kick in again after a while. Fianlly it stopped kicking on at all.

I pulled the blower motor and hooked it up to the battery direct. It works. I also test lighted the plug that goes into the motor (no power there on any setting). I am thinking it might be the relay, but haven't been able to find that. Where is it? ALso, where does this ground? I can't find that either.