VMS controlof Tile Heat

Im the happy owner of a 2007 CC Magna 630 with a VMS240 CL. The VMS controls the tile heat in the floor. The heat is zoned front and bathroom- the front heat does not work and the bath heat is fine. The resistance measurement for the front heat grid is in spec and the voltage to/from the GFI that powers the front grid is correct. How does the VMS control the grid and where is the thermostat that controls the VMS?

re: Tile heat

The weak point in the system is the device that handles the high current. Commonly its a relay somewhere. In your Magnas' context, its handled specifically by a solid state 'puck' located under the fridge. They're super reliable. But, all good things come to an end, someday.

Look under there for something just smaller than a pack of ciggies. Usually black with a metal base plate and usually screwed to something metal (with heat conduction compound 'grease') between them.
The outputs can be switched around to another puck to confirm the failure.

The sensor is under the main mat somewhere and is tied in via the TM-102 (Center bay compartment with inverter) . Output plug, pin 10 (top row, 3rd pin from the left.) Between that pin and ground, with it Unplugged, you should read about 4~12 k-Ohms.
It sounds like the sensor is fine but the specific a puck for that mat has failed.
This puck here is a good match for most in this category and amperage. Yours may look different... so this bigger list has many to choose from. Note: many of these are new in the box. Some are not. Compare the new ones with those on Amazon with the same specs. Amazons a bit higher but not bad.