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No Brake lights!

Sluggo: I don't disagree with you, but....

The Original Poster implied that when he examined the voltage coming out of the brake light switch (I'm assuming, of course, that the output line was not connected through to the turn signal switch) he was getting 9V. If that was true, then the turn signal switch is not part of the equation.

The brake switch is an order of magnitude cheaper, both in cost and time to replace, than the turn signal switch. I thought it would be worthwhile to at least explore the chance that it was the brake switch first.
 
If it's any consolation Mid, I'd change out the brakelight switch also. It couldn't take more than 5 minutes to have a new switch installed.
 
I guess you missed the two posts where he stated that stepping on the brake pedal caused the flashers to stop flashing.

Does this little trinket of information not indicate that the brake light switch is in fact closing the circuit? :show

If the brake light switch is inoperative, how pray tell would it have any effect on the flashers? It's one wire in and one out right?

Two other relative statements he made were:

9 volts on green with red wire (he thought)
0 volts on the other side of the connector.

I'm assuming this check was made with the connector disconnected.

We need a pot stirring smilie.....I'm gonna get on that.
 
I did not miss that at all. In electrical troubleshooting, the best thing to do is to first isolate as much as possible the various contributors to the problem, and test each in turn. I like to test the easiest first, then progressing to the most difficult to diagnose. I find that this method is the quickest and cheapest to resolving the problem.

I first recommended removing the 4 way flasher from the circuit, and trying to see if he had brake lights and all other functions. This isolates the 4-way flasher. He said that did not help. Next, isolate the brake switch, and see what the input/output voltages are of the switch. At that point, he said 9V out. Wouldn't you then assume that the brake switch was worth replacing? If he did not isolate the output line, then yes, I would next move to the turn signal switch.
 
Having re-read all of Tarafied's posts, here's the low-down:
No brake lights under normal conditions.
When using 4-way flasher, rear lights stop blinking when brakes are pressed (this is expected, as the fronts should stop blinking as well).
With 4-way flasher disconnected, still no brake lights.
9 VDC at one lead into the brake switch, 0 at the other. Jumpering the brake switch still yields no brake lights at rear.
Rear brake lights don't flash with 4-way blinker, but front ones do. (This is contrary to description above).
Rear running lights (separate filament) and turn signal indicators work.

With 4-way flashers enabled, you should see all four corners blink.
With 4-way flashers enabled and brake depressed, all four corners should be on and no blinking.

With all of the above, I would agree that the problem is at the turn signal switch or the connector to the turn signal switch. First, I would ensure that the green/black wire going to the turn signal connector at the base of the steering column is making positive contact. If that is true, then the problem is in the turn signal switch itself. The switch is a mechanical/electrical connector, and is often gummed up with grease and dirt, which can affect the electrical continuity. Remove the positive battery terminal, remove the steering wheel, and clean the turn signal switch (use electrical spray cleaner with small straw into the guts of the part just under the steering wheel. You should try and lightly pull it out of the base to access the guts). Try everything again. If still no positive results, then replace the turn signal switch.
 
What I got from his statements was that he had 9v coming in and 0v on the taillight side. Which makes sense albeit the input voltage is low.

Tarafied probably thinks we are about to rumble :show

No such luck Tarafied. We are simply hardheads locked in a spirited debate.

This is how I understand the circuit.

Voltage is supplied to the brake light switch on the green/red wire from the headlight switch.
We all know headlight switches on theses cars drop voltage cuz they suck. Hence the 9v reading.

Brake light switch outputs voltage to the turn signal switch on the green wire when the switch is closed (normally open switch) Simplified, the brake light switch connects the green/red wire to the green.

The turn signal switch outputs voltage to the brake lights and the rear direction signals on the orange/blue and green/orange wires. This is why you can not have brake lights and flashers at the same time. The rear lights are completely isolated from the front by the turn signal switch.

The front turn signals are operated again by the turn signal switch on a separate circuit which has the indicators on the dash tee-d into the output side of the front circuit and run in parallel. This explains why the front is doing it's own thing, and the indicators mimic what the front does.

The turn signal switch is power by the headlight switch as well. It is fed on a yellow wire the is tee-d to the green/red wire for the brake light switch and runs in parallel.

Am I reading this right?
 
Yeah, you're right and I was wrong about the colors at the brake switch: green/black is the input side and green is the output side.

If Tarafied only found 9V on the input side, something is wrong from the input side, ala the headlight switch. If the 4-way flashers work on the rear w/o brakes and pressing the brakes does nothing to affect that situation, then I would suspect the headlight switch and not the turn signal switch.

Tarafied should disconnect the connector at the base of the steering column and measure the voltage at the green wire (from the brake switch) with and w/o the brake depressed.

For Tarafied and others, Sluggo and I are trying to show how one goes about trouble-shooting electrical systems; there is no one way that works for everyone. The give and take between us allows a better diagnosis: two heads are better than one.
 
I appreciate all the dialogue as it does help me understand the troubleshooting process. I'm back from NY so I will dig into it a little before I go to Chicago. One point that still needs to be clear, I do NOT have rear 4 way flashers. No Brake lights, no flashers. Turn signals in rear ONLY. I do know that the flasher and brake light share the same filiment and the way the flashers always worked befoe was that if they were flashing and you step on the brake they stop flashing and just stay on. That's why I mensioned the fronts do this so you would know that the brake light switch was doing something. Thanks again for all the help. I'll read thru these posts again a few times and check everything you all suggest.
One other thing, I did replace the headlight switch this spring with a good one from CJ Pony parts.
 
Okay, just double checked that the wire was dark green with a red stripe. I made some connectors to plug into it and rechecked it with the plug disconnected from the brake light switch. I got 12.5 Volts from the green/red wire. I jumped 12+ Volts across to the green wire and still no brake lights.
I'm going to clean and check the other connections and turn signal switch.
 
Here's the low-down:
No brake lights under normal conditions.
When using 4-way flasher, FRONT lights stop blinking when brakes are pressed (this is expected).
With 4-way flasher disconnected, still no brake lights.
12+ VDC at green/red lead into the brake switch, 0 at the green. Jumpering the brake switch still yields no brake lights at rear.
Rear brake lights don't flash with 4-way blinker, but front ones do
Rear running lights (separate filament) and turn signal indicators work.
With turn signal connector unplugged and brake switch jumpered, 12+ V at green wire
With turn signal connector unplugged and brake switch open, 0 V at green wire
Yellow wire at connector hot (12+ V) all the time.
Orange/blue wire 12+ V (flashing) with right turn signal on and green/orange 12+ V with left but nothing with brakes pressed/switch jumped.
Turn signal switch?
 
If you could have measured the green wire when disconnected and brake switch pressed, that would have been great, as we could finally resolve whether that was the issue or not.

I believe your turn signal switch or the green wire connecting to the turn signal switch connector is bad. The fact that your front lights stop blinking is due to the output line of the stop light switch over-riding the flasher input line of the 4-way flasher. That says to me the stop light switch is fine. Right after the output of the stop light switch, the line bifurcates: one to the 4 way flasher (that acts both ways) and the other to the turn signal switch. I believe the joint is at the turn signal switch connector. That to me says it is the turn signal switch.
 
One final point: an earlier post of yours indicated you have the dynamite sticks from a Cougar installed on your'67. I'm not sure how they work vis a vis regular lights, but I wonder if the turn signal lamps still use the same filaments. Is it possible the rear lights are bad?
 
"Midlife" said:
One final point: an earlier post of yours indicated you have the dynamite sticks from a Cougar installed on your'67. I'm not sure how they work vis a vis regular lights, but I wonder if the turn signal lamps still use the same filaments. Is it possible the rear lights are bad?
Click to expand...

Don't the stock rear lights work off a single bulb? How would the cougar set up work? I'm pretty sure it was used on a three bulb setup.
 
the bulbs are dual filament and have a brighter filament for the turn signal and brake. Both filaments light up when the turn signal and tail lights are on. I don't think it's a bulb issue. I also measured 12+ volts at the wires which feed the bulbs. The Cougar lights have three bulbs rather than the Mustang single bulb. I added them when I put in the Cougar/Shelby lights. That does raise the question though, could it be the dynamite sticks have gone bad? They are STS-1 universal system, web site
www.webelectricproducts.com/products.htm
 
I was going to post and ask if you had dynamite sticks, but I didnt want to go back and read all the other posts to see if you had already mentioned it.
 
Well, Tarafied? What's the latest news? Both Sluggo and I have a rather large wager on what you find...heh heh.
 
Well I just got home from Chicago late last night and today I went to the Goodguys Nostalgia Nationals at Beach Bend Raceway. I ordered a turn signal switch since I'm pretty sure the brake light switch is okay. I'll let you know once it's in. I was gonna snag the turn signal switch from my 68 but it's different. I might try disconnecting the STS-1 gadgets just to see what happens.
 
Ok, you lazy sonofa...what's the story?? It better be my answer, or I'll never hear the end of it from Sluggo.
 
while I am lazy and won't deny the sonofa... either, my biggest problem is I'm never home. In fact I'm working this weekend in Vegas so I'm flying the wife out too. I can only sit in the hotel room thinking about fixing things most of the time. As soon as I get some time at home I'm gonna tear into it. I wasted my last couple of days at home dragging home another Mustang. I did change the brake light switch and dimmer switch and it didn't fix it so I'm hoping the turn signal switch is the fix.
 
It can be arranged for you to become self-unemployed, so you'd have all the time in the world to work on your cars. Just let me know. BTW, I do work for the gubbermint...Well, let me re-state that...I get paid by the gubbermint.
 
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