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I'm struggling to get my brake lights working and not sure where to look now. I installed a new hydraulic switch yesterday and still no joy. I had my kid press the brake pedal to tested continuity at the switch. That checked out fine. I'm not a stellar electrical guy. My question is how the switch operates. Is the line always hot and the switch completes the circuit or is it a ground and the switch completes the ground? If it's always hot, I can begin there to see if I have power or not and work my way back.
Is your system 6 volt or 12 volt? Are there 2 wires on switch? If it is 12 volt do you have a clip tester with the point and internal light?
Should be able to use process of elimination. Establish where power is and follow to next point. Good luck and let us know if you find your problem
You should have an "always hot" lead going to the stoplight switch. It's just a simple single contact diaphragm pressure switch. You didn't state what you're working on, but that's it in all Ford, Dodge, and GM truck schematics.
Sorry, I should have said in my original post. 1950 f1 with the straight 6. 12 volt now.
That's what I was hoping or expecting Bob (the always hot lead) that's a good starting point for me. With that I can use my voltage tester to check that it's hot coming in and work back towards the tail lights from there. I obviously have a ground since the tail lights work and it's shared between the tail lights and brake lights. This is the stupid little thing keeping me from playing on the road with it more.
No worries. Actually, the year, make and voltage doesn't matter because almost all vehicles are wired that way. I think I recall seeing something in FMVSS-108. Peruse at your convenience if you get bored. https://www.gpo.gov/fdsys/pkg/CFR-20...sec571-108.xml
From what I remember, you can purchase a new brake light switch which turns on the brake lights at a lower pressure than the standard switch does. I believe that is what I put in my truck when I noticed that my brake lights didn't come on as quickly as I wanted and didn't come on during very light braking. This other switch fixed the problem.
No worries. Actually, the year, make and voltage doesn't matter because almost all vehicles are wired that way. I think I recall seeing something in FMVSS-108. Peruse at your convenience if you get bored. https://www.gpo.gov/fdsys/pkg/CFR-20...sec571-108.xml
Bob,
the only thing worse than reading it is that my taxes paid for someone to write it !!!
Bob,
the only thing worse than reading it is that my taxes paid for someone to write it !!!
Originally Posted by raytasch
OMG, that is painful to read. Ya reckon there was a committee involved! Agree with jnolon.
The two jobs I had that involved the Feds had required reading from the CFR's. I swear to God reading them was the equivalent of downing a cap full of ZzzQuil.
I had looked at that but figured with my 10 year old barely pressing on the pedal and me getting continuity below - I was good. I'm going to try to eliminate a few more things then may go that route. I looked at the Harley switch the other day. It had flat terminals on it. Easy enough to swap my connectors I suppose.
With the engine running use a jumper wire across the brake light pins. The brake lights should come on. If they do not check for 12v coming from the dash (this is most likely problem area). If none then that is where your problem is. If there is 12v then check at each socket also. If none then there is a broken wire between the switch and the tail lights.
[QUOTE=petemcl;18095890]With the engine running use a jumper wire across the brake light pins.
? The brake switch should be hot ALL the time weather the engine is running or not. You should be able to step on the brake pedal with nothing turned on in the truck and have brake lights.
Mark
With the engine running use a jumper wire across the brake light pins.
? The brake switch should be hot ALL the time weather the engine is running or not. You should be able to step on the brake pedal with nothing turned on in the truck and have brake lights.
Mark
Depends what mods have been made. The Ron Francis basic kits shuts it off. Better for a beginner to test with it running.
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