I was told that my brake pressure switch is bad and was wondering where this is located and if there are any instuctions on how to replace it? I have a manual and all I can find is the switch for my brake pedal.

 

What year? Do you mean the proportioning switch for the front to rear brakes? Need a little more info.

 

Who told you it was bad? Brake warning light been coming on/staying on? The problem may be the brake system and not necessarily the switch.

Under the hood, beneath the master cylinder and (possibly) close to the frame rail. You will see brake lines and one electrical wire running to it. Most are copper/brass colored.

The AIM shows the installation. Chassis service manual may show replacement. Replacement will require bleeding the brakes.

 

I took it in to a garage when my brake light on the dash came on. He said that I needed to replace the brake pressure switch and the parking brake switch saying that one or both were bad. I'm leaning towards the master cylinder went bad again because of the lack of pedal hardness. The light doesn't always come on because I drove to work abot 15 miles and nothing but everytime I go to put the brakes on I always give it a pump or to for confidence. If the light does come on I step on the brake again it goes off. They took off all my wheels and said I had no leaks but the pedal isn't as hard as it was before the light started coming on and off. The fluid is always full and had the master cylinder replaced 2-3 years ago. I looked in my manual and they show this pressure switch on the combination valve and is not sold separatly. I'm kind of lost what to replace becaues of the costs involved. The master cylinder is the cheaper of the two but find it hard to believe it would be bad already.
I drive this car everyday and don't want to loose my brakes.
By the way the mechanic said that the brakes were good just ignore the warning.... I have a hard time with that and believe this guy 100%. He's never worked on my car before and don't know how really good of a mechanic he is.
Thanks for your help!

 

He's guessing. The emergency brake switch might be a little loose, but you can tighten that. It's at the base of the e-brake handle.

May not be the master cylinder. If the switch is operating correctly, air in the system would make the BRAKE warning light come on.

Extremely bad advice. Time to look for a better shop.

Have the system bled. Master cylinder and all four wheels.

 

Find another mechanic as he doesn't know what he's talking about. The proportioning valve switch is working just fine. Bleed the brakes to see if the pedal improves.

Gary

 

and easy to do.

 

If you have air in one circuit, then the spool in the combo valve must be operating fairly freely to be able to gain enough pressure on the second pump to compress the air enough to reset the spool and turn off the lite. It usually takes a fair bit of differential to set or reset it.

Given you have no external leaks, sounds more like a cup on one circuit of the master is failing, and yes, they can easily go bad in a couple of years due to a number of factors.