In the early 2000s, car manufacturers began installing a new system in cars called a "tire pressure monitoring system." This system monitors the inflation of your vehicle's tires and alerts the driver when the air pressure a tire is low. Prior to the law requiring TPMS on all vehicles manufactured from Sept. 1, 2007, only some vehicles had TPMS systems. The 2007 Mustang was one of the few that came with this system without the law in place. Resetting the tire pressure light in the 2007 Mustang is not much harder than adding air to your car's tires.
Allow the tires to cool off, if you just finished driving -- the tire's pressure rises as its internal temperature rises.
Open the driver's door and locate the vehicle information placard on the doorjamb. Read the correct psi tire rating on the placard and notate this pressure.
Remove the valve cap from one tire.
Press the valve part of a tire pressure gauge onto the end of the valve stem. Read the pressure displayed on the pressure gauge and notate this pressure. Compare this pressure reading to that you have noted from the vehicle information placard.
Release air from the tire, if the pressure in the tire is too high, by pressing the small pin in the top of the valve stem with a small flat-head screwdriver. If the tire is low on air, add air to the tire, using a compressed air source and a tire chuck.
Repeat Steps 4 and 5 until the tire is within 2 psi of the pressure recommendation on the vehicle information placard. Tighten the valve stem cap back onto the valve stem.
Repeat Steps 3 through 6 to check and adjust the pressure on all four tires.
Start the Mustang and drive it for approximately two minutes at a minimum speed of 20 mph -- once all four tires are at the correct pressure -- to reset the tire pressure light.
