First be sure the reservoir level is not too low. The pressure differential switch moved to turn on the warning light when a leak in one of the two hydraulic circuits prevented it from building the same pressure as in the other circuit. On most cars that switch is spring-loaded and will reset automatically but sometimes they stick. Usually a good hard and quick jab to the brake pedal will pop it free. If that doesn't work you will have to open the other circuit, have a helper slowly push the brake pedal until the light goes out, tighten or close whatever you opened, THEN the helper can release the pedal.
The Ford engineers were too cheap to put springs in their pressure-differential valves. Those are extremely frustrating to reset. You have to again open the other circuit, push the pedal very slowly and watch for the light to go out, stop immediately, and tighten whatever was opened. It is common for the valve to shift to the other side so quickly you don't see the slight flicker in the light. At that point you don't know if you didn't push the brake pedal far enough or if the valve moved too far. They make special tools to install in place of the switch to hold the valve centered while the rest of the system is being worked on but you have to install it before that valve moves. Lot of good that does when it moves as the result of a surprise leak. I don't know if your valve is spring-loaded since it's an import but start with a hard jolt to the brake pedal.
During bleeding you must never ever push the brake pedal more than half way to the floor if you use a helper. Doing so will usually damage the master cylinder. If that happened you will not get the warning light to go out until the master cylinder is replaced.
Wednesday, April 10th, 2013 AT 11:00 PM