A link to the product would help with what advice to give.
I'm assuming this is wired and two wires are coming from the window?
If so, get a cheap meter and put it in 'ohms' or resistance. Connect the meter to the two wires (don't get your fingers touching the ends of the probes as this will influence the resistance reading) and read the resistance in the open and closed position. Report the results back here and we can help.
If they have more details on the installation, post the PDF also.