| First, check passenger compartment (under dash) and power distribution box (under hood) fuses. A Haynes manual might allow you to know if there's anything else on the brake light circuit that could cause a problem. Learn to use a DMM (or test light) to check fuses quickly and accurately, without running the risk of replacing one in the wrong slot. Second, look for any corrosion in the sockets (disconnect neg. battery terminal before cleaning). Best to use silicone dielectric grease on base of bulbs to prevent problems. Third, use DMM or test light to probe connector and see if power is flowing, as someone else pushes the brake pedal. Fourth, check circuit out by following it backwards to the battery. Fifth, most Fords have a brake light switch on the brake pedal arm under the dash. Run a continuity check on it and see if it needs replacing or adjusting. | 
Linear Mode
