Proportioning Valve Question

[MIDEVIL214]

I'm adding a new prop valve to my power disk/drum brakes. I had the warning light (74) disconnected for years but decided to hook it up again with the new valve. I spliced the two violet (purple) wires together like Toms and WH suggests. I did a quick test before installing the lines and my warning light stays on when the harness is disconnected from the prop valve switch. It also stays on when connected to the uninstalled prop valve.

Should the light stay on with the harness connector removed from the valve switch? I even removed the switch from the valve and connected the harness. The light stays on...

I'm familiar with the re-centering process once the lines are hooked up. Just worried that its not going to matter because the light seems to stay on no matter what.

http://www.tomsbroncoparts.com/pages/schematics/bronco-schematics/drivetrain/66-77-early-ford-bronco-proportioning-valve-diagram/

 

[Viperwolf1]

No it shouldn't stay on if it isn't connected to the valve. The problem is going to be under the dash at the ignition switch proof circuit. That is where the light circuit gets a ground when the valve doesn't provide it. It's done at the ignition switch as a bulb test. That proof circuit should only be grounded when the ignition switch is in the START position. Maybe the ignition switch is bad or maybe someone rewired the light.

 

[MIDEVIL214]

Thanks, I will have to look at the ignition switch. The ignition switch seems to be functioning correctly but it has been removed a few times over the years. Bulb shouldn't have been rewired though as it worked fine with the stock h-block valve for the 20 years I've had it.

So splicing the two factory switch wires together to fit the new single wire switch wouldn't cause the light to stay on?

 

[Viperwolf1]

So splicing the two factory switch wires together to fit the new single wire switch wouldn't cause the light to stay on?

No. Those wires were connected together inside the stock imbalance switch.

 

[mnido]

Calling Viperwolf

No it shouldn't stay on if it isn't connected to the valve. The problem is going to be under the dash at the ignition switch proof circuit. That is where the light circuit gets a ground when the valve doesn't provide it. It's done at the ignition switch as a bulb test. That proof circuit should only be grounded when the ignition switch is in the START position. Maybe the ignition switch is bad or maybe someone rewired the light.

Question Viperwolf, you have been very helpful with other wiring issues I have asked you about and I want to Thank You ! Now for another if you don't mind in regards to the proportioning valve. I am using a non Bronco wiring harness on my build. When it come to the proportioning valve on my build, how do I wire it as a stand alone circuit utilizing the warning light ? Does that make sense ? Thanks! ( sorry for the hijack !)

 

[Viperwolf1]

Question Viperwolf, you have been very helpful with other wiring issues I have asked you about and I want to Thank You ! Now for another if you don't mind in regards to the proportioning valve. I am using a non Bronco wiring harness on my build. When it come to the proportioning valve on my build, how do I wire it as a stand alone circuit utilizing the warning light ? Does that make sense ? Thanks! ( sorry for the hijack !)

Thanks. I try to be helpful.

The switch on the valve is just a switch. It's normally open but will provide a ground when there is an imbalance. Connect the this to one side of the bulb and switched power to the other side of the bulb.

 

[mnido]

Thanks. I try to be helpful.

The switch on the valve is just a switch. It's normally open but will provide a ground when there is an imbalance. Connect the this to one side of the bulb and switched power to the other side of the bulb.

So, wire from valve to one side of warning light, other wire from warning light to 12 volt source ? And Thanks Viperwolf !

 

[bronconut73]

Also Do not mean to hijack...
But,
Ain't Viperwolf cool?...
I mean seriously man....thank you for all of your help...

 

[MIDEVIL214]

No. Those wires were connected together inside the stock imbalance switch.

Ignition switch and bulb are both good. Verified with another switch as well. Also removed all the wires off the back of the ignition switch post except the one factory looking black one. Light still comes on in the run position with the prop valve wire disconnected from the valve and hanging free.

I did notice that the light will not come on when the ignition switch is loose from the dash. Once the rear switch spacer makes contact and grounds at the dash the light comes on.

 

[Viperwolf1]

Ignition switch and bulb are both good. Verified with another switch as well. Also removed all the wires off the back of the ignition switch post except the one factory looking black one. Light still comes on in the run position with the prop valve wire disconnected from the valve and hanging free.

I did notice that the light will not come on when the ignition switch is loose from the dash. Once the rear switch spacer makes contact and grounds at the dash the light comes on.

That would indicate the ignition switch is not good.

 

[MIDEVIL214]

Second new switch fixed the problem. The first replacement I bought had the same warning light issue that the stock one did. It also would crank in the run position and prime the fuel pump in the off position.... glad thats all over for now.