Plug identification and brake help!

[DirtDonk]

If your two green lights illuminate when you hit the brakes, most likely your turn signal switch wires are incorrect. The green lights are for the turn signals only, and should only illuminate with the front turn signals.
Do your front turn signals or running lights come on with the brake too? Or is it just the indicators on the dash?
If just the indicators, then it's the turn-signal switch wiring. If the front AND rear lights come on, then something else is amiss. Maybe wiring, maybe grounds, maybe something else entirely? Not sure of all the possibilities, but we've seen it before here so maybe someone has some insight.

The Brake Warning Lamp (or imbalance indiator, or whatever it's proper name is) would be (or have been) on the dash near the ignition switch. Little round red light with a chrome bezel around it and the word "BRAKE" in the red lens. Looks like this: Brake Warning Lamp Lens & Bezel
After '67 when the dual-circuit master cylinders were introduced, and the H-block on the frame was used, there was a simple switch on the H-block that would be activated by a sliding piston in the H-block that would sense if there was an imbalance (fluid leak) in either the front or rear brake circuit. Here is the switch that would match your connector: Brake Pressure Imbalance Switch
If you have a leak in a rear hose for instance, the shuttle/piston/thingy would slide over that way, trip the switch, and the dash light would illuminate.
The circuit is wired also, so that when you turn the key to the START position the light comes on momentarily as well. It's a bulb and circuit test to let you know it's working. Like modern warning lamps do today, only mechanically tripped rather than controlled by a computer.

Do you still have that lamp on the dash I described? Does it ever come on?
Often people think it's for a parking brake (would make sense) but that's not it. Can be made to do that with some fabbing, but is only to indicate a leak.
Most of the time, after a few years of use, the light comes on and nobody can figure out how to turn it off again so they either leave it until it either melts the lens or burns itself out, OR they unplug it.

That's the long version. In your case, with the H-block gone and a new proportioning valve it sounds like, yours may no longer function.
Is your prop valve a manually adjustable one with a knob? Or is it one of the brass block types? If the latter, then there is probably a switch on that one that could have been connected to the wires in your pics to make the dash light work again.

Paul

 

[zerostar2410]

If your two green lights illuminate when you hit the brakes, most likely your turn signal switch wires are incorrect. The green lights are for the turn signals only, and should only illuminate with the front turn signals.
Do your front turn signals or running lights come on with the brake too? Or is it just the indicators on the dash?
If just the indicators, then it's the turn-signal switch wiring. If the front AND rear lights come on, then something else is amiss. Maybe wiring, maybe grounds, maybe something else entirely? Not sure of all the possibilities, but we've seen it before here so maybe someone has some insight.

The Brake Warning Lamp (or imbalance indiator, or whatever it's proper name is) would be (or have been) on the dash near the ignition switch. Little round red light with a chrome bezel around it and the word "BRAKE" in the red lens. Looks like this: Brake Warning Lamp Lens & Bezel
After '67 when the dual-circuit master cylinders were introduced, and the H-block on the frame was used, there was a simple switch on the H-block that would be activated by a sliding piston in the H-block that would sense if there was an imbalance (fluid leak) in either the front or rear brake circuit. Here is the switch that would match your connector: Brake Pressure Imbalance Switch
If you have a leak in a rear hose for instance, the shuttle/piston/thingy would slide over that way, trip the switch, and the dash light would illuminate.
The circuit is wired also, so that when you turn the key to the START position the light comes on momentarily as well. It's a bulb and circuit test to let you know it's working. Like modern warning lamps do today, only mechanically tripped rather than controlled by a computer.

Do you still have that lamp on the dash I described? Does it ever come on?
Often people think it's for a parking brake (would make sense) but that's not it. Can be made to do that with some fabbing, but is only to indicate a leak.
Most of the time, after a few years of use, the light comes on and nobody can figure out how to turn it off again so they either leave it until it either melts the lens or burns itself out, OR they unplug it.

That's the long version. In your case, with the H-block gone and a new proportioning valve it sounds like, yours may no longer function.
Is your prop valve a manually adjustable one with a knob? Or is it one of the brass block types? If the latter, then there is probably a switch on that one that could have been connected to the wires in your pics to make the dash light work again.

Paul

The dash lights only come on when i brake, nothing else. My turn signals also don't work and that was next on the project list. I did install a new column a few years back so maybe i got some of the wiring pins in the wrong location?

I do have the little red brake light on my dash that has never come on. My new proportioning valve is the brass block type and did come with a pigtail to wire in the brake warning light. Maybe ill give it a shot to check that little light on the dash out. Is there anyway to differentiate the two wires on the old pigtail? is one hot and the other ground? Guess i would probably figure that out with my volt meter.

 

[DirtDonk]

The dash lights only come on when i brake, nothing else.

The dash lights are part of the front turn signal circuit. So yes, if they come on only with the brake lights, then you have the "turn signals" backwards. Remember the brake lights, rear hazard flasher lights, and rear turn signal lights are the same circuit from the steering column all the way back to the rear bulbs.
This may, or may not be related to your turn signals not working, but almost guaranteed the wiring at the column is wrong.

My turn signals also don't work and that was next on the project list.

You might fix one thing, only to find out it fixes three.

I did install a new column a few years back so maybe i got some of the wiring pins in the wrong location?

This is the most likely scenario. Nothing is guaranteed of course, until you track down the culprits. But it's got a very high probability at this point.

I do have the little red brake light on my dash that has never come on. My new proportioning valve is the brass block type and did come with a pigtail to wire in the brake warning light. Maybe ill give it a shot to check that little light on the dash out.
Is there anyway to differentiate the two wires on the old pigtail?

It's an odd circuit. You simply twist both of the old purple wires together and splice both into the single black wire of the new proportioning valve switch.
Should work like a charm...

Check the side of your ignition switch too. When all is normal, there is a "proof out" connector on the side of the body of the switch. This grounds the switch to the dash when you turn the key to START.
On this terminal will be one of the Purple wires, or it could be Pink. When everything is working as expected, the BRAKE warning lamp will come on during START. Then it will go out when the key is released into the RUN position.
With luck, it will go back out. So many of them have been stuck in the on position for so long people just unplug them.
Not as big an issue with the new design, but with the old H-block it's rampant.

Paul

 

[zerostar2410]

Alright so I twisted both purple wires together and connected them to the single black wire of my proportioning valve. Didn’t work. I began to trace the wire loom back to find out the wires had been cut and connected with butt connectors. Not sure why this was done and some of the colored wires didn’t match up. Cut the cheaply done butt connectors off, soldered wires, and applied shrink tubing. Still didn’t work. Anybody know if these wires are correctly matched up?

Green to green
Orange to red
Black/red to blue
Brown to brown
Yellow to yellow

Or maybe the bulb is already burned out?

 

[Rustytruck]

when you start the truck the brake warning lamp will light and then go out if the system is working properly.

If you start the truck and the light lights and doesn't go out it is assumed working properly then the the brake distribution block has tripped due to a brake malfunction. That means the switch is stuck or there is a brake fluid pressure imbalance and the brake system needs to be checked and repaired.

If the brake warning lamp does not light at all when turning the key on then the bulb is burned out, a wiring problem or a bad ground issue to the lamp. At this point I would check the bulb and go from there. I would also look at a wiring diagram for your truck to check and understand how the system is wired.

 

[zerostar2410]

when you start the truck the brake warning lamp will light and then go out if the system is working properly.

If you start the truck and the light lights and doesn't go out it is assumed working properly then the the brake distribution block has tripped due to a brake malfunction. That means the switch is stuck or there is a brake fluid pressure imbalance and the brake system needs to be checked and repaired.

If the brake warning lamp does not light at all when turning the key on then the bulb is burned out, a wiring problem or a bad ground issue to the lamp. At this point I would check the bulb and go from there. I would also look at a wiring diagram for your truck to check and understand how the system is wired.

Bulb works now!

A wiring diagram would be awesome. Where can I find one?

 

[DirtDonk]

There are links here and there on the forums to member Steve83's customized wiring diagrams that would help. I think they go back only as far as '74, but that should be perfect.

They're on his SuperMotors pages, so if you don't find any recent references here, you can search SuperMotors directly for anything by Steve83 which is his username there too.

Now, that all said, just when does your lamp work?
And some of those other colors don't seem legit. Is that how they were matched up before? Normally there is only one Red w/blue wire colored circuit, and that's for starting the engine.
Something doesn't seem right, but I have not checked diagrams yet to verify.

Paul

 

[DirtDonk]

The lamp circuit is relatively simple, in that it has only two colors. Runs like this:

1. The Pink w/white wire connects from the ignition switch's proof-out ground to one side of the switch on the H-block.
2. Out the other side of the imbalance switch is Pink w/white until it reaches the lamp.
(the thing to remember is that both the ignition switch and the imbalance switch are possible grounds to complete the circuit. So either one by itself can turn on the lamp)
3. Out the other side of the lamp, the wire is colored Red w/yellow.

When the key is in the ON position, a potential of 12v is at the Red w/yellow wire and the lamp in the dash. It does not do anything yet, because the lamp itself is not grounded. Hence nowhere for current to travel, therefore no light.

When you turn the key to START, this grounds the Pink w/white circuit and turns on the light.
When your brake balance is out of whack, the switch grounds out on the H-block and the light comes on.

Pretty simple in wiring, but having so many possible things going on, it actually feels pretty complicated. Even after years of fiddling with it!:-[

Paul

 

[sykanr0ng]

Bulb works now!

A wiring diagram would be awesome. Where can I find one?

These may help:

http://seabiscuit68.tripod.com/

If you want laminated ones for shop use:

https://www.classiccarwiring.com/ford-truck/

 

[zerostar2410]

There are links here and there on the forums to member Steve83's customized wiring diagrams that would help. I think they go back only as far as '74, but that should be perfect.

They're on his SuperMotors pages, so if you don't find any recent references here, you can search SuperMotors directly for anything by Steve83 which is his username there too.

Now, that all said, just when does your lamp work?
And some of those other colors don't seem legit. Is that how they were matched up before? Normally there is only one Red w/blue wire colored circuit, and that's for starting the engine.
Something doesn't seem right, but I have not checked diagrams yet to verify.

Paul

Sounds good. Thanks!


The light turns on during “START” and turns off when engine fires. I reconnected the wires exactly how I found them. I haven’t taped and loomed anything yet because I wasn’t sure if the wiring was correct