one more painless question brake warning

[4x4man514]

thanks for all yalls help. it has really made a difference in my harness install. and im almost done so i can leave yall alone lol.

im not sure i understand the function of the brake warning light.

the original switch if i remember right was on the h block of the brake lines and im pretty sure ive done away with that

i have the wild horses moab/wilwood brake system and on the proportioning valve there is a switch

does this replace the original warning light or is this supposed to be a signal for brake lights?

thanks again for all yalls help!

 

[DirtDonk]

Without looking at it at the moment, I'd say NO it is not the same.
Usually the switch on the Wilwood valves is a pressure sensing brake light switch. Meant for hot-rods and custom builds with custom brake systems that do not incorporate a brake light switch on the brake pedal. It senses the pressure applied to the system by your foot on the pedal and turns on the brake lights.
Since your Bronco likely still has a brake lamp switch on the pedal and the brake lamp wires from the Painless harness attach to that, the switch on the Wilwood valve is left blank.

In fact, you can even blank out the switch itself if you want to. Simply remove it and install a pipe plug in it's place.
Or leave it there in case your brake lamp switch ever fails in the middle of nowhere and the state police pull you over for non-working brake lights. You can fix it right there!
Certainly not a very common scenario, but something to mention.

Ok, now having said all that I guess I'd better go look to see for sure!

Paul

 

[Matt@Wildhorses]

Paul, you are spot on. The pressure switch on the valve now, would activate the lights, on pressure, like a brake light switch. If the warning light was hooked to it, it would light up every time you press the brake pedal. Really, the switch on the valve is only used or needed in the 66's that did not have a switch on the pedal. The pedal switch and a plug in the valve is the best route. We have heard of some switches being fragile and leaking.

My $0.02

Matt

 

[4x4man514]

got yall thanks.

what was the original purpose of the switch exactly??

 

[jamesroney]

Without looking at it at the moment, I'd say NO it is not the same.
Usually the switch on the Wilwood valves is a pressure sensing brake light switch. Meant for hot-rods and custom builds with custom brake systems that do not incorporate a brake light switch on the brake pedal. It senses the pressure applied to the system by your foot on the pedal and turns on the brake lights.
Since your Bronco likely still has a brake lamp switch on the pedal and the brake lamp wires from the Painless harness attach to that, the switch on the Wilwood valve is left blank.

In fact, you can even blank out the switch itself if you want to. Simply remove it and install a pipe plug in it's place.
Or leave it there in case your brake lamp switch ever fails in the middle of nowhere and the state police pull you over for non-working brake lights. You can fix it right there!
Certainly not a very common scenario, but something to mention.

Ok, now having said all that I guess I'd better go look to see for sure!

Paul

Paul, you are spot on. The pressure switch on the valve now, would activate the lights, on pressure, like a brake light switch. If the warning light was hooked to it, it would light up every time you press the brake pedal. Really, the switch on the valve is only used or needed in the 66's that did not have a switch on the pedal. The pedal switch and a plug in the valve is the best route. We have heard of some switches being fragile and leaking.

My $0.02

Matt

Hi, Matt, you are close...but not 100% correct.
The pressure switch used by Wilwood does indeed function as you describe, but it is a SPST contact and has two male spade connectors.
If you were to connect the two wires from the 67-77 Bronco harness to the two spade connectors...the only thing that would happen is that the brake hazard warning light would illuminate with the key in the start position ONLY when the pedal is depressed.

So yeah, you could light up the light ever time you press the brake pedal...but only while cranking.

For those that don't know...(and I know that you and @DirtDonk know this...the two wires on the H-block are there because the system wants to know if the valve is connected. You could connect the two wires together anywhere...and then run a single down to the h-block if you wanted to. All the H-block does is ground the wire when the shuttle valve moves.

 

[jamesroney]

got yall thanks.

what was the original purpose of the switch exactly??

Original purpose of WHAT switch?

 

[4x4man514]

the warning light. why would you see it in the original configueration?

and if i dont use it do i need to do anything with the wires? im guessing probably not.

thanks

 

[Matt@Wildhorses]

@jamesroney, I appreciate the clarification. Close, but no cigar, as the saying used to go...

 

[jamesroney]

the warning light. why would you see it in the original configueration?

The brake warning light is an indicator to the operator that there is a significant imbalance between the front and rear hydraulic circuit. Generally speaking, the rear hydraulics can fail, and you won't know it until you really need the brakes.

So the OEM installed a balance detection valve in the system, between the two master cylinders. If you look at your dual chamber master cylinder, it basically behaves as if it were two master cylinders. There's a reservoir and piston for the front brakes, and a separate reservoir and piston for the rear. When you depress the pedal, both hydraulic lines flow fluid to each half of the car. If there is an imbalance, the shuttle valve moves, and grounds the connector on the h-block. If that is grounded, it illuminates the dash warning lamp. To ensure that the lamp is good, and the system is intact...there is a additional ground lug on the ignition switch that makes momentary contact to ground in the start position. So if the H-block is connected, and the ignition switch is in the start position, the lamp will illuminate.

 

[4x4man514]

The brake warning light is an indicator to the operator that there is a significant imbalance between the front and rear hydraulic circuit. Generally speaking, the rear hydraulics can fail, and you won't know it until you really need the brakes.

So the OEM installed a balance detection valve in the system, between the two master cylinders. If you look at your dual chamber master cylinder, it basically behaves as if it were two master cylinders. There's a reservoir and piston for the front brakes, and a separate reservoir and piston for the rear. When you depress the pedal, both hydraulic lines flow fluid to each half of the car. If there is an imbalance, the shuttle valve moves, and grounds the connector on the h-block. If that is grounded, it illuminates the dash warning lamp. To ensure that the lamp is good, and the system is intact...there is a additional ground lug on the ignition switch that makes momentary contact to ground in the start position. So if the H-block is connected, and the ignition switch is in the start position, the lamp will illuminate.

thamks a bunch. now i understand it

so is it worth getting another switch and hooking it up or do i need to just cap the ends of those wires and call it a day. what do most people do?

 

[DirtDonk]

With this system, I believe it is intended to keep the standard H block on the frame, is it not? If so, then, keep the wires connected to the original switch and call it a day.
If this particular design eliminates the H block, then that’s another matter. But I’d be willing to bet that most Broncos whether stock or modified have that switch wiring just hanging loose in space because at one time or another the light came on and would not go out. Even when the brake system was fixed.

 

[4x4man514]

With this system, I believe it is intended to keep the standard H block on the frame, is it not? If so, then, keep the wires connected to the original switch and call it a day.
If this particular design eliminates the H block, then that’s another matter. But I’d be willing to bet that most Broncos whether stock or modified have that switch wiring just hanging loose in space because at one time or another the light came on and would not go out. Even when the brake system was fixed.

got ya. thats prolly what im gonna do. mostly because i dont even have a switch right now and i would need to buy one. which is no big deal but if i pull the plug and install it then i guess i would need to go back and re-bleed the brake system again.

 

[DirtDonk]

Nope, should not have to re-bleed.
At least not normally.

You should be able to just unscrew the old one and put in the new one. If everything else is still working.
What makes you think that you need a new one?

 

[DirtDonk]

Oops, sorry. Only took me three seconds to forget you said yours was missing.

 

[4x4man514]

yea so i was looking at the h block or trying to and i realized the window for messing with that switch has come and gone. lol. headers and everything else is in the way. so i dont really need it anyways.

question is do i need to connect the two wires in the harness? or just make sure they dont connect to anything? ive already tied the other end to the trouble light on the dash.

thanks! for everything guys!

 

[904Bronco]

No it doesn't need to be hooked up. Just secure it out of the way...

The brake light will not illuminate when you start the Bronco, this was just a test to insure the system was working.

 

[jamesroney]

yea so i was looking at the h block or trying to and i realized the window for messing with that switch has come and gone. lol. headers and everything else is in the way. so i dont really need it anyways.

question is do i need to connect the two wires in the harness? or just make sure they dont connect to anything? ive already tied the other end to the trouble light on the dash.

thanks! for everything guys!

What does this mean?

"I was looking at the h-block and I realized the window for messing with that switch has come and gone." What switch are you talking about? The switch in the h-block for system imbalance, or the brake lamp switch in the Wilwood distribution block?

Do you need to connect what two wires, in which harness? Or makes sure that what doesn't connect to anything? The other end of something went to the trouble light on the dash? I don't have any idea what that means. What are you trying to fix, and what are you trying to defeat?

The brake hazard warning lamp system has 3 functions. It illuminates when the brake pressure between the front and rear have a significant loss. It also illuminates to indicate the function of the lamp warning system. It also illuminates to detect the presence of the sensor.

So when you turn the key to "start" the system detects whether the h-block sensor is present, and lights the lamp. This way, you know that the sensor is there, and the bulb is working. This is a critical safety feature on the Bronco, it is the ONLY electrical safety feature, and there is absolutely no reason to defeat it from working.

The bulb in the dash is powered by the ignition post from the ignition switch. The filament on the bulb is energized with +12V any time the key is on. The other half of the filament is floating. If you ground the "floating" half of the filament...it lights up. It is the ONLY lamp in the dash that operates this way. This is why it has 2 wires attached to it. One is always at +12, and the other is looking for a ground. The funky terminal on the ignition switch that looks like an afterthought on the outside connects to ground when you turn the key to crank. The post on the H-block switch connects to ground when the balance valve is shifted. The two posts on the H-block connector are a shunt to connect the two wires that go there together.

Hope that helps.

 

[DirtDonk]

yea so i was looking at the h block or trying to and i realized the window for messing with that switch has come and gone. lol. headers and everything else is in the way. so i dont really need it anyways.

If the H-block is still there and the switch intact, you're saying you can't even get in there to plug in the new harness?
The Painless harness comes with (at least I thought it did) a new 2-wire connector already installed on that circuit. Isn't that the case with yours?
Or are the two wires just loose and unterminated?

question is do i need to connect the two wires in the harness? or just make sure they dont connect to anything? ive already tied the other end to the trouble light on the dash.

Since you already have it connected to the lamp, and presumably the wire to the ignition switch Prove Out connector as well? Are you just running the H-block, or do you have a combination/proportioning valve plumbed into the system somewhere as well?
At this point I see you have two or three options.
1. If the new harness does indeed pre-terminate the wires with a proper connector, you can somehow reach in there through the headers and other plumbing and snap the connector to the switch. This way you have a fully functioning safety circuit.
2. If no-go on the switch, you can twist the two wires together to complete the circuit so the lamp comes on for testing only. Probably not worth the trouble since you would defeat the purpose of the circuit.
3. If you have a 1-wire switch somewhere else such as in a separate combination valve, you can twist the two to the one and still have a functioning system.
4. You can, as discussed already, simply tuck them out of the way and ignore them.
5. My Plan-B if not using the switch, or even if still using it, would be to add a new switch to your parking brake pedal and use the lamp as a warning light to indicate the parking brake is applied. The switch would ground the circuit anytime the parking brake is applied.

Plan-A would be to continue to try to get the connector on to that existing switch and have a working safety device AND make a secondary branch to a new switch on the parking brake pedal.
This would presume that your safety imbalance switch is in fact working and not just stuck in the CLOSED position of course. Which would leave the light on the dash illuminated at all times!

Good luck.

Paul

 

[4x4man514]

thanks for all the info guys. i think im good on how it works at this point. the more that i think about it i dont even think i have a h block any more. the moab kit came with a bracket that secured the hoses to the frame and the front and rear circuits are not even connected. sorry guys i dont even know why i didnt think about that earler.

the warning light i have is not factory its merely a small led with two wires coming out of it so im assuming that worked the same as the original switch and thats why i attached the two wires in the painless harness.

paul, i really like your plan b idea. im terrible about forgetting my parking brake. is there a switch that is made for the pedal assembly? or what have yall used to make one? and would i just attach the two wires in the harness to the two wires of the switch in that scenario?


thanks a bunch to everyone here helping me out. i owe yall one. hopefully one day ill be able to repay yall with some knowledge!
kevin

 

[DirtDonk]

Don't know of a ready-made switch and bracket, but it's pretty straightforward as accomplished by just a few here over the years.
And yes, pretty sure you'd simply attach the two wires so that with power coming into the lamp on one side, then out to the switch on the other. Then the switch would have the one coming in from the lamp, and the other one theoretically just going to a good ground.

What type of switch you choose would depend on where/how you mount it. Whether a "normally open" or "normally closed" switch would work better for this will depend on whether you want the switch touching the pedal when it's at the top of it's stroke (parking brake OFF) or when it's pushed downward (parking brake ON) and stuff like that.
Seems like it would be a normally closed switch mounted up so that it's pushed in when the pedal is up. This turns the lamp off when the pedal is up, but as soon as the pedal goes down even one small notch, the switch would go back to closed and would light the light.

Seems to me anyway.
Hopefully someone that's actually done it will chime in.

Paul