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Hello, need some help.   I installed a brake light switch from Pantera electronic and it worked perfect until the shop I brought my car to messed them up.   I even bought a new unit from Jon to see it they broke it but same issue. I had the shop replace the brake booster and proportioning value.   I have checked the fuse, power to the switch and the running lights.   All seem to be ok.   I disconnected the wires to the BLS and ever other lights seem to work perfect inside and out or the car.   But once the ignition is on, not even running starting the engine, thr brake lights come on and never turn off.  Any help would be appreciated.   I have finally got this car running and road ready, but still can’t take it out due to this issue.    Thanks again, Dan

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Most likely the plunger in the brake distribution block needs to be reset. The block is the brass H shaped thing in the front trunk.

The low brake pressure sender screws into it in the middle.

Once it senses low pressure in either the front or rear system, the internal plunger engages the switch and sends voltage to the brake light.

This can happen during a brake line failure or installation of new brakes in the car.

If you just put brakes in the car and paid someone to do it, don't use that shop again. This would be an inexcusable mistake by the shop indicating they are dangerous numb nuts and do not understand the brake system in your car.

Now to cop an attitude like "but I never saw anything like a Pantera" doesn't cut it either. The same system is used in the Mustang from it's inception until computers took over.

If it's your fault, shame on you. Go sit in the corner.

Well it wasn’t my fault, thank god.  I hate sitting in the corner.  But to your point on the shuttle valve, how do you reset it?  Does the brakes have to be bleed dry and start over or is there an adjustment on this thing?   Also, is it the line coming from the brake booster?   I am a fairly competent shade tree mechanic, but have never work on one like this before.  Thx Dan

When you say brake lights stay on do you mean the lights at the rear of the car or the small warning light on the dash? If you mean the rear of the car the shuttle valve has nothing to do with that. If you mean the warning light then yes, either the shuttle valve has activated or the emergency brake handle is not fully released.

Sorry could have been more clear.   When the ignition key is on, engine running or not, the brake lights are always on.   I have checked the wiring from the brake switch and it all checks out. And I have a stock brake systems except for the brake light switch from Pantera electronics.   Everything works perfect, before they shop replaces the brake booster and master cylinder.   The brakes, calipers rebuilt and lines were all replaced last year.   So everything in the system is new and stock.  

Thank you for all the advise.   I eventually took the PE brake light switch out only to find the adjustment screw was completely adjusted wrong, and the locking nut wasn’t even tight.   Took my time to get everything adjusted properly, then reinstall the brake light switch and now it’s working.   Still needs some fine turning, but working.  

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