morning,  been a while since i've posted, but i am getting close to having 5k miles since i got this contraption back together.  no major issues yet.  that being said, realized the brake lights were out yesterday.
all other lights are working, ...running, turn signals, dash, dome, backups, ...step on the brakes, nothing, on either side.
i have stock setup, drums all way round.
i checked the continuity of the master switch and it's working.  tried shorting the two green wires together, nothing, im thinking i should have voltage on one of those wires, correct?
where's the next place i can check for voltage or continuity, the light switch?
 
-Swank

The brake light switch should be live all the time.  The green wire gets power from the 'A' post of the headlight switch.  Check the headlight switch for 12v on the green wire.

ok, pulled the light switch out the dash board, no voltage on post A (second tab from back on left side, green wire with green connection cap, just like the wires on master cylinder switch).  noticed the 7.5A fuse was blown.  replaced it, had 12v on post A.  got someone to come stare at the taillights while i stepped on ghe pedal, ...no brake lights at all.   tried all the other lights, they all still work the same.  tested for voltage on post A again, ...nothing.  pulled the fuse and now the new one is dead also. 
the wiring diagram gives me the impression that the fuse should be for the dome light.  the dome light works with no fuse in at all.  i have a green wire with yellow cap connected directly on a vertical tab on the left side of the fuse (this tab has voltage with no fuse installed).  the green wire with green cap is on the horizontal tab right before this one.  these colors seem to match up with the correct colors on the switch diagram.  so, with no fuse even in the switch, i can get voltage on all the correct tabs (depending on running lights, or headlight, etc), ....except for the horizontal tab second-from-back on the left (green wire, green cap).
is the 7.5 fuse for the stoplights?, if so, afraid i might have a short somewhere else, ...?, or might my light switch be going bad?   
any thoughts or direction on where to start chasing from here would be appreciated. 

the wiring has been the same for the last 5000 miles, brakes lights just stopped working in the last few days. 

-Swank

I had this come up last week on my hardtop.  I have the original Turn Signal Switch with all the wires.  Check the connections at connectors.  The on/off of the brake switch goes through there. 
So if your brake switch is hot on one  side, you press on it or jump it and still don't get brakes, go to the TSS

I found I had two loose crimp terminals.

I happen to have kept my original TSS. But wires it to a GM style harness.

There are three green wires coming from the switch.  Two of them should power up once the pedal is pressed.  Those activate the rear brake light.

Hopefully this helps.

evening update.

the first thing i checked was the continuity across the master switch, which was fine and seems like it still is.  ohms drop to next to zero when pedal is pushed, returns to 1 when you let up.  this was with the wires removed.
next checked for voltage going to turn signals (thanks Abe), ...nothing.  pulled the battery cable then checked continuity from turn signal to master switch, then from master to light switch, then checked orange and green wires from dash to taillights, ...all good.  put the battery back, then shorted across the two master switch green wires, tail lights came on.  put the green wires back on the master switch, had voltage on one post, but no brake lights.  checked for voltage on the other post with pedal up and down and with the wire on and off, ...nothing.  pulled the green wires, checked continuity across the switch again, seemes good. 
for some reason, the master cylinder brake light switch will pass the ohms test, but doesnt want to carry voltage. 
autozone trip, new master switch, and 10 bucks later, the brake lights are in full service. 
now just have to bleed the brake lines real good.

in messing with all this, i partially disassembled the light switch, seems the very back left vertical tab and the second-from-back left horizontal tab, even though attached to the switch with the same screw, is actually separated by an insulated washer and doesnt seem to make contact with each other.  so, what is supposed to run through the fuse, the dome light circuit (green wire with yellow cap), or the brakelight circuit (green wire with green cap)?

-Swank

 thanks for the update. 
Glad you figured it out.

I have used 3 brake switches in different cars in the past 3 years or so. Although the oem switches were designed to carry the full Amperes load for both brake lights without a relay, the new ones are just cheapish crap that can't stand the power for extended usage. the copper contacts simply burn inside. I'll dig up a pic from last year, where I cut one apart.

The fuse is for the dome lights.

Quote from: Ford Blue blood on 2022-09-06 08:11The fuse is for the dome lights.

thanks, looks like brakes and dome have been backwards the whole time. 

-Swank

Quote from: djfordmanjack on 2022-09-06 02:58I have used 3 brake switches in different cars in the past 3 years or so. Although the oem switches were designed to carry the full Amperes load for both brake lights without a relay, the new ones are just cheapish crap that can't stand the power for extended usage. the copper contacts simply burn inside. I'll dig up a pic from last year, where I cut one apart.

I agree, I have converted several to mechanical switch on the brake pedal and done away with the hydraulic switch all together.

James

Quote from: djfordmanjack on 2022-09-06 02:58I have used 3 brake switches in different cars in the past 3 years or so. Although the oem switches were designed to carry the full Amperes load for both brake lights without a relay, the new ones are just cheapish crap that can't stand the power for extended usage. the copper contacts simply burn inside. I'll dig up a pic from last year, where I cut one apart.

X 3

follow up.

Duralast switch, the only one available from the local-yocal bigbox parts place, lasted aprox 5 minutes.  Started leaking between the metal casing and plastic connection insert.   Finally found just a regular "standard motors" switch,  good so far.   Gave me a good bit of bleeding practice though.

You are not going to find quality replacement parts at a BOX-STORE ...

Quote from: KULTULZ on 2022-11-12 11:09You are not going to find quality replacement parts at a BOX-STORE ...

heard that.   thats what i get for attempting convenience.   instock and 2 minutes from the house?, ...too good to be true.