Tpms question

Your truck has 4 sensors, not five. Set your spare to 45 PSI. If you don't see a nail in the "leaking" tire it could be leaking from the O-ring around the sensor itself (called the fit kit). You just need to change the fit kit not the entire sensor.

Someone told you incorrectly about the "reset" switch. Set your tires to 20 PSI, turn the key on, hold the switch (for how many seconds? I forget), turn the key off , set the tires to the pressure for normal driving. Now your "threshold" is set.

I've had my 2012 for maybe 2 and a half years, my thresholds were set when I put the new tires on and I never see the light come on, even when it gets real cold.

 

The OP's truck is a 2007. Don't want to beat a dead horse here and, as many have already stated the 2007 is set up to read 5 sensors, one of which is for the spare tire. The ECM needs to see that 5th sensor befor that pesky light goes away.

 

I know right!