brake warning switch

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dvav

dvav

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rewiring my car and was wondering if the warning light is just connected to the park brake or does it get wired to the prop valve too. also what does the prop valve switch do .is it to let you know if there is a leak. if so do I even need to wire to the prop valve
 
Yup. It gets wired to both.
But heres the thing. It gets wired to what is commonly called a proportioning valve. That valve may or may not be a proportioning valve. It depends what its out of and how its configured. If it has an electrical connector on it, then thats what you wire it to. The light will indicate when there is an imbalance in pressures between the front and rear hydraulic circuits of a dual brake system. Such as when you blow a brake hose. Of course when that happens, you will know it, as the pedal goes down and the car is harder to stop. So the light will be confirming what you already know. But if a hard line is leaking, or there is another non-catastrophic leak, it will inform you of that as well. And that would be a good thing.
 
Exactly. In front disk cars, it is termed "combination valve". In drum cars, a "distribution block". Both have the "imbalance warning" switch, since ~1968. Either that switch or the parking brake switch can short to ground, causing the lamp to light.

My 1996 Voyager is the same (even w/ ABS added to the combo valve), but adds a 3rd "MC reservoir low fluid" warning switch. Any of the 3 can short to ground to light the lamp. I recently dug thru that when the light stayed on after a fluid refresh and poor info in the manuals. Turned out to the reservoir float had stuck. I expect all 1990's Mopars were the same. If you change to a later MC w/ level sensor (as I did), you now know how to simply wire it in to also light that lamp.
 
When I converted the dash brake warning light to LED, the light is always on dimly and go full bright when I put on the parking brake. If I put a light bulb back in, it is either on or off, no in-between.
It does annoy me when it is the LED, but you learn to ignore it.
Although it is the only dash LED that does this
 
AJ/FormS said:
Doesnt that indicate a voltage leak there somewhere? I would think so.What happens when you remove the two known voltage sources; one by one?
Click to expand...


The wiring to the oil and brake light is always hot and only come on when the switch grounds them. I am not using the oil pressure light. I use the switch to turn on and off power to the fuel pump.
sitting here thinking about it, I should probably remove the wire to pin 11 on the dash pcb. That may solve the problem. I am not going to disassemble the dash just for this. I will do it next time I have to take it apart.

Which my not be that much longer as I may rewire the components to the firewall connector. If you do not follow that, it is ok, I know what I mean
 
LED's don't take much current, usually 1.5 V give a visible glow (in the dark). Voltage drops in the common returns could do that. With LED's in my M-B, I noticed the "brake pad worn" lamp slightly glows when raining (visible at night). It normally lights when the sensing wire in the pad touches the rotor. The slight conduction thru the water is enough to give a slight glow.
 
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