Does any one know if ford puts a tpms sensor in the spare tire?

I got a flat yesterday and went to a gas station and put enough air in it to get me home. When I got home I put my spare on and dropped off the bad one at the tire store to get repaired. I drove to work today and then home agian on the spare and my tpms light never came back on. The light was on yesterday when I had the flat and went out when I aired up the tire. I'm thinking there is a fifth sensor in the spare and as long as the system sees at least 4 good signals, then your golden.

Another possibility is the sensors only send out a signal when the pressure is too low and since I was out off range of the low tire, the system never picked it up and never set off the light.

 

They do not put one on the spare. It does take some time for it to come on. A constant above 25mph for about 20 min. If your commute is short or stop and go it might not come on. Eventually you will get a sensor fault and the light will flash 75 times, then come on steady.