From viewing a similar answer for a '95, and upon personal inspection, it appears to be behind and above the drivers side fuse panel. If you remove the black panel below the steering column, I think that you will see the socket assembly for it behind the left side of the instrument panel. Perhaps more later as I conclude this myself.
According to the 2009 Ford Escape Owner Guide : ( # 24 is a 20 amp fuse for the horn relay )
Ron Horn was born on 1938-05-24.
Harald Horn was born on February 24, 1925.
Darrin Horn was born on 1972-12-24.
I have changed horn modules on a 1994 Cougar, which should be the same from 1993 through 1997. There were two horns (one low-pitch, one high-pitch) located in the engine compartment located near the bottom of the radiator, one on the left and one on the right, about 24 inches apart. The Ford service manual I located the parts in indicated that for my 1994, the dual-horn configuration was normal.
George Henry Horn died on 1897-11-24.
Stories of the Century - 1954 Tom Horn 1-24 was released on: USA: 1 July 1954
Doug Van Horn was born on June 24, 1944, in Sedalia, Missouri, USA.
James Van Horn was born on September 24, 1917, in South Dakota, USA.
Smurfs - 1981 A Myna Problem The Horn of Plenty 6-24 is rated/received certificates of: Australia:G
Smurfs - 1981 A Myna Problem The Horn of Plenty 6-24 was released on: USA: 1 November 1986
You will need an interpose relay. This relay will have a 24 volt coil. The circuit power for the relay will come from a 120VAC to 24VAC volt transformer. The 24 VAC circuit will have the thermostat in series with the coil of the relay. Thermostat calls for heat, the coil energizes and the relay's contacts close. Your circulator pump is controlled by the relay. On selecting the relay make sure that the contact ratings can handle the full load amps of the circulator. A contact rating of 120 volts at 15 amps will do very nicely.