Alright so I got the aftermarket Proportioning Valve today and Dad is stumped.
So this thing has got one lead and Dad says we need two, so he asked me to ask ya'll if any of you have done this? Do I have to get another thing with two leads? or is there some sort of switch or relay? or is there a way to hook up with just the one lead that I just don't know about


Any Help would be great, articles to point us to or just your own knowledge.
Thanks in advance

 

Need to post a pic or schematic if you have it. Need more info.

 

I just ran into this same issue and wondered if you ever came up with anything. I bought an aftermarket pro valve from Broncograveyard. I figured I would look on here and see if there was an easy solution before I go hit the wiring diagrams.

 

He just told me and I am drawing a blank Will get back to you tomorrow after I ask him but if I don't bug me on my account email so I will

 

If I remember it has a 2 prong single connector thats goes to the "Brake" warning light in the dash. Not where I could ck right now or would for you, guess a wiring schematic would help.

Does the JBG valve only have one lead connector point? Seems to me they would sale a 2 lead one????

 

It does have a 2 lead and I believe you are right the second goes to the brake light but if you ask the guys where you got the valve they will tell you to just ground it to the frame and that is NOT what you want to do.
Also check this link here on this site I remember my Dad saying it helped
https://www.ford-trucks.com/forums/9...alve.html:-tap

 

Typically when a switch has one lead, it's a switched ground connection. For example, this is how the oil pressure warning light is set up - power is applied to one side of the light, and the other side of the light is tied to the switch. When the oil pressure is high enough, the switch is open, and the light is off. Once oil pressure drops enough (usually 5 psi), the sending unit grounds the lead to the sending unit body. Because the sending unit threads into the block and is grounded, the light comes on. I'd assume this is the case for the aftermarket proportioning valve, since typically the valve bolts to the frame, which should be grounded through a ground strap (although sometimes the connection is lost over time).

As far as the 2-lead connector for the factory setup, a lot of factory brake light warning switches I've seen are plastic, so the warning switch is isolated from ground and can't ground the light. This is why there are two leads coming from it. Instead of grounding out the light as would be done in a one-lead switch, the two leads are shorted to turn the light on. Without seeing a schematic of the factory wiring coming from the dash, I can't make a recommendation on how to wire it. It depends whether the switch switches power or the return.

There are only so many ways a simple on/off switch can work. If it has one lead, it's meant to switch to ground when closed. In that case, the switch has to be mounted to a grounded point (such as threading into the engine block). If it has two leads, the two leads are shorted together when closed.

 

Can you post pictures?

 

I will post pics today. I am still trying to figure this one out.

 

I am looking at the wiring diagram (my truck is a 74 but these diagrams are for a 78) I am pretty sure this part of the system is similar. It looks like it grounds at mount. One of the two wires runs to the cluster gauge for the light, and the other wire runs to the ign switch (for pwr?)I will see if I can post these on here. These diagrams are posted in a thread...it may be easier to search the thread.

 

The original plug(2 wire) The new(1 wire)


new plug and pro valve switch

 

I looked at mine today and it is not even connected. I believe all that does is activate the light or dummy light. Anyone know what this does?

 

It tells you if you have a loss of pressure. The valve locks out the front or back whichever one is leaking to prevent complete brake failure. It pretty much tells you to stop as quickly as you can. I am debating not even worrying about hooking it back up. I am making an autometer gauge cluster and I am not sure where I want to put the light anyhow.

 

Maybe that is what is up with my whole brake set up. I thought it was the master cylinder, but if that is what that proportioning block does maybe I should check that. It almost feels like I am ridding the rears and if I mash the pedal it will lock the rears. I have to pull it apart tomorrow. But I have never had mine hooked up and everything was working until one day and who know how old the master is.
Keep me updated on what you decide and what you do and how she runs.
Mike

 

I think FMC is right when hooking it up it is an open/ close circut.