Issues with brake lights

Cars used to have them just above the arm on the brake pedal. You look there? It was a simple switch, in - off, out - on.

 

there is an air psi switch behind your dash if you remove cluster there is a switch with 2 pins thats your signal light switch you will know cuz you turn ign on and jump the terminals your brake lights will come on just replace the switch should have 1/4 black airline going to if if memory serves me correctly.

 

next question what happens when the air line is unplugged and you press your brakes do you have full air psi at brake switch or does it lag and then kick in. line should go on the firewall behind the clutch pedal see if the line is kinked somewhere just take a blower and test out the lines that line should in some way be connected to the foot valve or the front treadle valve just dont recal exactly where it would be.

 

it shouldnt be hard to figure out just got to take it step by step. make sure you got good air from what you are decribing air is mission somewhere doesnt seem like it is electrical so far.

 

did you by any chance mix up the positions, of the hoses, there is a way you can test it directly from the valve, if memory serves me right there should be 4 supply on the foot valve and 4 brake lines if you can tap into one of the green air lines one the delivery side so when you press the brake this is the only time they get air put a t in one of those lines and from the t reduce the fitting to 1/4 run hose directly to brake signal switch and see what happens there is a small possibility that you might also have a bad foot valve over time the pistons go farther and farther back so they start making problems like this as well, this way you just make sure you have a good air line and it goes directly from delivery system on the foot valve hose has no kinks nothing so you know you got good hose if same result then you have to replace foot valve.