Brake light

[JeeperjohnfromPA]

My Comanche is very close to being 'put on the road', but I've one slight problem with the brake light. It stays on.

When I first aquired this beast several months ago, both brake lines to the rear were rotted away and leaking fluid. I realize that this would cause the sensor in the proportioning valve to cause the light to illuminate.

I have since replaced the brake lines to the rear, yet this light will not go out.

In the past My jeep CJ8 and also on my YJ the brake light in the dashboard, (ie parking brake light), has come on on various occasions when there were problems other then the braking system.

I realy want my MJ to work the same way.

 

If I disconnect the wire for the sensor in the proportioning valve the light goes out.

This makes me think that this valve in the proportioning system is stuck, has anyone had this problem?

Is there an easy fix? I realize most of you prolly did away with the rear proportioning valve and switch to an XJ proportioning valve in the front.

But there must be some other knucklehead out there, who, like me, is trying to keep using the rear proportioning valve.

could it be that I have the lines that go to the rear proportioning valve mixed up?

 

Any advice that anyone could give, (other then do away with the rear proportioning valve), is greatly appreciated.

 

Thanks john

[mjeff87]

You have to reset the switch inside the prop valve. Per the FSM, you have to apply 500 psi to the brake system to do that (inside the cab, press the pedal down hard). Way back when one of my rear lines first blew I had the same problem after I repaired it....I tried the reset method mentioned and it didn't work. I ended up repacing the prop valve (even though the brakes were working fine).

 

Jeff

[oldjeep]

If you use a pressure bleeder, it resets all by itself.

http://www.motiveproducts.com/02bleeders.html

 

best $65 I ever spent

[HOrnbrod]

My Comanche is very close to being 'put on the road', but I've one slight problem with the brake light. It stays on.

When I first aquired this beast several months ago, both brake lines to the rear were rotted away and leaking fluid. I realize that this would cause the sensor in the proportioning valve to cause the light to illuminate.

I have since replaced the brake lines to the rear, yet this light will not go out.

In the past My jeep CJ8 and also on my YJ the brake light in the dashboard, (ie parking brake light), has come on on various occasions when there were problems other then the braking system.

I realy want my MJ to work the same way.

 

If I disconnect the wire for the sensor in the proportioning valve the light goes out.

This makes me think that this valve in the proportioning system is stuck, has anyone had this problem?

Is there an easy fix? I realize most of you prolly did away with the rear proportioning valve and switch to an XJ proportioning valve in the front.

But there must be some other knucklehead out there, who, like me, is trying to keep using the rear proportioning valve.

could it be that I have the lines that go to the rear proportioning valve mixed up?

 

Any advice that anyone could give, (other then do away with the rear proportioning valve), is greatly appreciated. Thanks john

 

I had this problem many moons ago when I first got my MJ. Turned out to be a shorted brake switch under the pedal. And yes, I'm one of those knuckleheads :mad: who still retain the rear load sensing valve and it works just fine.

[JeeperjohnfromPA]

I'll double check the wires in the brake pedal switch/assembly.

But Like I mentioned, when I disconect the wires from the front proportioning valve it the problem is gone.

 

As for the presure bleeder, Aggg throw more money at this Truck!

I'll check with a few friends before investing in one.

 

Gonnna need money for some new tires on my YJ and this MJ to get through inspection soon.