1. The Most Obvious (and Easiest to Check First):
* Bulbs: The most common cause is simply burned-out brake light bulbs. Check all three bulbs (two on the back and one on the high-mounted stop lamp (CHMSL) – the third brake light on the top of the rear window). Replace any that are burnt out.
2. Fuses:
* Brake Light Fuse: Check the fuse box (usually under the hood and/or inside the cabin) for a blown fuse specifically related to the brake lights. Your owner's manual will show you the fuse box layout and which fuse controls the brake lights.
3. Brake Light Switch:
* Location: This switch is usually located near the brake pedal. It's a small switch that activates when you press the brake pedal.
* Testing: You can test this switch with a multimeter to see if it's sending power when the brake pedal is pressed. If it's not, it needs replacement. This is a relatively inexpensive part.
4. Wiring:
* Corrosion: Check the wiring harness leading to the brake lights for any signs of corrosion, damage, or loose connections. This is particularly important at the connection points.
* Broken Wires: A wire might be broken somewhere along its run from the switch to the lights. This is harder to diagnose and may require tracing the wires.
5. Brake Pedal Position Sensor:
* Some vehicles use a sensor to determine brake pedal position. A faulty sensor could prevent the brake lights from functioning.
6. Central Electrical Issues (Less Likely):
* Body Control Module (BCM): In rare cases, a faulty BCM can cause brake light issues. This is usually diagnosed by a professional mechanic.
* Ground Issues: Poor grounding can disrupt electrical circuits.
Troubleshooting Steps:
1. Check the bulbs first. This is the quickest and easiest check.
2. Check the fuses. This is also relatively quick and easy.
3. Inspect the wiring harness. Look for obvious damage.
4. Test the brake light switch. If you're comfortable with basic electrical testing, this is a good next step.
5. If the above steps don't solve the problem, consider taking your Sport Trac to a qualified mechanic. They have the tools and expertise to diagnose more complex electrical issues.
Remember to always disconnect the negative battery terminal before working on any electrical components in your vehicle. Safety first!
