brake warning light

[Talan423]

i recently re-installed my tailights, panel etc.... they hadn't been in the car for over 3 years. when i now start my gt/cs the brake warning light comes on and stays on (on the dash cluster). has anyone else had this problem. could this be a grounding problem? i anybody has any suggestions, i'm all ears.

thanks
tom

 

[68sunlitgold]

tom,
If I am not mistaken the brake warning light comes from you brake pressure differential valve, did you check the connection there? I attached a pic of one with warning light wiring circled (and the valve is one from a Mercury not Mustang, same valve different attachment hardware). Also did you check the flluid level? Hope this helps.
Doug

 

[68sunlitgold]

Tom,
Found more info in the Shop Manual about "Warning Lamp Stays Lit", it could be one of the following:
1) One section of dual brake system is inoperative
2) Differential pressure valve is not centered **
3) Wiring to warning Lamp or switch is grounded
4) Warning Lamp switch is grounded

** There is a 4 step process to correct this, shop manual states "to centralize the pressure differential valve and turn off the warning light
1) Turn the ignition switch to the ACC or ON position. Lossen the differential valve assembly brake tube nut at the outlet port on the opposite side of the brake system that was bled last. Depress the brake pedal slowly to build line pressure until the pressure differential valve is moved to a centralized poition and the brake warning light goes out; then, immediately tighten the oulet port tube nut to the specified torque ***
2) Check the fluid level in the master cylinder reserviors and fill them to within 1/4 inch of the top with the specified brake fluid, if neccessary
3) Turn the ignition switch to the OFF position
4) Before driving the vehicle, check the operation of the brakes and be sure that a firm pedal is obtained

*** Torques
3/8 - 24 thread 8-15 ft pds
7/16 - 24 thread 10-18 ft pds
1/2 - 20 thread 12-20 ft pds
9/16 - 18 thread 15-25 ft pds

I hope this additional info solves the problem

Doug