Ford E9LY-13480-A Stop Light Switch Assembly

The engine coolant temperature sensor works like a thermistor that changes its power through temperature shifts, and its connection circuit can show trouble by triggering certain problems. Start by finding out how well the sensor works: take the cold and warm resistance readings, then see if warming the sensor makes the resistance go down. Check the voltage sent from the PCM to make sure the resistance values are accurate. To put in the new sensor, wait until the engine cools down fully, cover the threads with special tape, and treat the sensor gently to keep it from getting hurt. The MAP sensor takes readings from the intake manifold pressure, turns them into electrical voltage, and gives this information to the PCM to decide how much fuel to release and when to ignite the fuel. During MAP sensor electrical troubles, special fault codes show up. You can check the MAP sensor by looking at both reference voltage and signal voltage with a voltmeter, then put the system under vacuum and watch for tachometer activity. The PCM reads the oxygen content in the exhaust through the oxygen sensor. The sensor provides electrical input that tells the PCM when to add or reduce fuel in the air/fuel mixture. The MAP sensor works best when the electrical components are connected right, it gets the air it needs, runs at the right temperature, and only uses fuel without lead. Make sure the oxygen sensor gives a constant reading once it warms up, then look to see if its heating element gets power from the battery. The TPS, found on the throttle body, reads how open the throttle valve is to send correct fuel to your engine. You can examine TPS performance by measuring voltage at idle and full throttle, plus looking at PCM reference voltage. The Mass Air Flow (MAF) sensor tells the PCM how much air goes into the engine by converting it into a changing electrical voltage value. To find out if the MAF sensor is working, look for power and voltage at the signal, and check the wire for any breaks. The MLP sensor tells the PCM where the transmission is, which controls different features. Check if the MLP sensor works correctly by making sure the signal wires have the correct voltage. Combinations of problems with the Vehicle Speed Sensor lead directly to a determined fault code. To inspect the VSS, make sure the signal voltage is present at the connection. The Intake Manifold Temperature Sensor tells the PCM how warm the incoming air is, making the PCM work properly. You should measure voltage and resistance in the Intake Manifold Temperature Sensor while testing it to see how temperature affects its readings. A faulty power steering pressure switch can cause problems maintaining proper idling by monitoring fluid pressure. Your car can't tell where it's going without working crankshaft and camshaft sensor signals. Seek out a qualified mechanic to fix location problems that pop up. The brake system lets the PCM know when drivers push their brakes. When checking this part, we look for the brake light system's electricity as well as how connected points are from the brake light bulbs.

To remove the brake light switch assembly, start by removing the under-dash panel. Next, locate the switch near the top of the brake pedal and disconnect it by removing the retaining clip. To install the switch, snap the clip into place on the electrical connector. Reconnect the assembly to the brake pedal and reinstall the under-dash panel.

In dual tank models, verify proper electrical operation of the fuel pump relay, inertia switch, fuel pump(s), fuel injectors, and fuel tank selector switch.

The switch should activate within the first 1/4-inch of pedal travel.