I have a 92 thor pinnacle 454 engine.I have a brake light lit up on the instrument panel.I went to check the fluid but couldnt find the master cylinder anywhere.I ran the lines from the caliber to the master cylinder and found it.If anyone is familiar with this vehicle and know what i am talking about how do you get to the master cylinder to check the fluid?I can see it from under the vehicle but i wouldnt be able to see the fluid even if i got it open.

My '84 Tasca had a cutout in the floor under the carpet.Otherwise, you take the LF wheel off.

Eversince the light came on seems harder to stop.Could it be the fluid being low or something else?Before hand always felt a little spongy but now more so.Almost scary.If i pump them they will get better.

That light will come on if the pressure in the part of the cylinder that operates the front brakes is different from the part that operates the rear. So, if fluid has gotten so low that one part isn't applying and the other IS, then the light will come on.I've seen this happen on vehicles and it's usually time for another master cylinder. One part is working and the other is leaking internally.

Access to my master cylinder is through the left front wheel well. I have hydraulic jacks that when fully extended makes it easier to go over the top of the wheel.The light could be on because of a problem with the auto-park if equipped on your rig. My light is on when rig is in park, and then goes off when in neutral or a drive position.

As J-D said, an imbalance in the hydraulic system, either from low fluid which can be caused by disc pad wear, or an internal leak will cause the brake warning light to come on. If you find tha fluid is low, be sure to find the cause, don't just add fluid and be done. If the fluid isn't low, it's probably an internal leak, and the master cylinder needs to be replaced. JMHO

master cylinder | Good Sam Community

enblethen
Nomad
Sep 01, 2015
I believe your issue will return.
joe0508
Explorer
Sep 01, 2015
Why should i be looking for the switch for the lighT?
enblethen
Nomad
Aug 31, 2015
The early OBD I do not monitor the brakes.
Look around the hydro-boost for the switch for the light.
joe0508
Explorer
Aug 31, 2015
Light went off after starting the rv and letting it idle for a few moments and than pumping the brakes slowly.
joe0508
Explorer
Aug 31, 2015
I tryed the codes and it just keeps flashing code 12.I looked it up and it says no codes stored.
joe0508
Explorer
Aug 31, 2015
I have front and rear disc brake.I am not sure about the lines but it has two seperate bowls in the master cylinder.I filled the steering fluid but it didnt turn the light off.Now i am trying to find the test port to ground the a and b port to start a troubleshoot with the check engine light.I cant seem to locate the test port.Do you have any idea where it might be?It is a 92 thor pinnacle on a p30 chassis with 454.
enblethen
Nomad
Aug 30, 2015
No, the brake indicator is on the brake fluid system.
Yes, low power steering fluid can effect braking.
I didn't see a reply as to whether you have drum or disc brakes in the rear.
Does your master cylinder have one or two lines exiting it?
MEXICOWANDERER
Explorer
Aug 30, 2015
Abandon ship!
joe0508
Explorer
Aug 30, 2015
My power steering fluid is low.Will this cause the brake light to come on?
enblethen
Nomad
Aug 30, 2015
OP:
do you have discs on rear or drum brakes?
Is the switch for the brake light warning indicator on the master cylinder or on the small block below the master cylinder on the frame?

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