Master warning light is on and I don't know why. Window washer fluid light also on which I can remedy. Would the master warner light be associated with the fluid light?

Check this link for all Nissan warning lights

Nissan Altima Dashboard Warning Lights and Meanings

The Nissan Master Warning Light, Explained
Basically, all the master warning light does is let you know that there's some other warning you should pay attention to. According to the 2015 Nissan Altima owner's manual, when the ignition is in the ON position, the master warning light will turn on with any of the following warnings:
-Loose fuel cap
-Door open
-Trunk open
-Low fuel
-Low windshield wiper fluid
-Check tire pressure warning
-No key detected (happens if the Nissan Intelligent Key is left outside the vehicle)
-Release parking brake (this should occur any time you start the car after setting the parking brake)
If your Master Warning Light comes on, please contact your local Nissan Dealer

Sharon, Check to make sure emergency brake is not on and fully released, try not to drive your vehicle if the red brake warning light is on. Could have air in the system from a small crack in brake line, faulty master cylinder, faulty caliper etc. Have a good tech. check braking system, diagnose and estimate repair.
Brake Warning Light
Brake Hydraulic System Red Warning Light
What do the brake warning lights mean in my car HowStuffWorks

For some reason these vehicles you need to bleed brakes several times, had same problem, so air hangs up in lines somewhere it apears. When you say brakes sticks, describe it better, locked up, or dragging on rotors?
CERACOAT-NANOTECH.com

Master cylinder fluid piston has entered into a brake safe mode.
when the high pressure brake system is opened in any way, the brake master cylinder piston reaches to the far end of the master cylinder which trips the brake system warning light.

This brake light condition is due to sudden loss of brake fluid pressure on the right front brake caliper assembly during the replacement.

Left rear brake caliper bleed valve will ned to be "opened" until master cylinder piston travels into the opposite direction which "resets" the brake system warning light.

Dot 4 brake fluid recommened for most, but not all vehicles.
Reference vehicle to owners manual for replacement fluid is replaced under master cylinder brake system cap.

Hello. Welcoem to FIxYa. Please allow us to assist you.

If the Brake warning light is illuminated on your instrument cluster, the cruise control is prevented from being set. This is normal.

The most common reason for the Brake light to be illuminated is low brake fluid in the brake master cylinder. As the brakes wear, the fluid in the master cylinder drops proportionally to make up for the wear on the brakes.

We sould suggest that you check the fluid level in the master cylinder. If it is low, top it off with a new can of brake fluid. Don't use brake fluid that has been opened, use new. Brake fluid that has been sitting in a can will draw moisture, and this moisture, when you put it into your master cylinder, may cause your steel brake parts (that touch the fluid) to rust.

If the fluid level is OK, you may have another issue; one that a trained professional needs to look at.

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Brake warning light.

If the light is on all the time, it could mean you simply forgot to release the parking (emergency) brake. The brake warning light remains on when the brake is set as a reminder. If the brake warning light remains on when the parking brake is released, then something is amiss.
In some cases, the brake warning light may remain on if the switch on the parking brake pedal or lever is misadjusted. Nothing is wrong with the brakes and a simple adjustment should fix the problem.
If the brake warning light comes on when you apply the brakes, or is on continuously, it means that hydraulic pressure has been lost in one side of the brake system or that the fluid level in the master cylinder is dangerously low (due to a leak somewhere in the brake system). In either case, the fluid level in the master cylinder should be checked. Adding brake fluid to the master cylinder reservoir may temporarily solve the problem. But if there's a leak, the new fluid will soon be lost and the warning light will come back on.

http://autos.yahoo.com/maintain/repairqa/warning_lights/ques010_0.html

• The majority of the time this is also an indicator that your brake fluid is below a safe level. Adding some brake fluid to the master cylinder and pumping the brakes a few times should remedy this.
• If this does not remedy this then you have a leak in the brake system somewhere or your master cylinder could be malfunctioning. Make sure the lid on the master cylinder is on tight and sealed well too.
• The master cylinder is where you fill the brake fluid. Do not over fill it.

Regards, tony

If the fluid is low on the larger section of the master cylinder, it is probably an indication that the front disc brake pads are becoming worn. As the pads wear, the caliper piston moves out of the caliper, requiring more fluid to displace it. Since brake pressure warning and low fluid warning use the same indicator light on the dash, if the brakes are operating normally, its probably not a serious problem. If you had an actual brake system fluid leak, the brakes would not work properly(low pedal, mushy feel, etc.)
You should have the front pads checked, just in case they need to replaced now, rather than just refilling the brake fluid because if you fill it first, then find out the pads need replacement, when the caliper piston is pushed back into its bore, it will push the fluid back into the master cylinder, overflowing the reservoir.
Because brake fluid is hygroscopic, meaning that it attracts moisture from the atmosphere, the water and any associated corrosion/gunk it collects will settle by gravity to the lowest point, the calipers. So, you do not want to push that junk back toward the master cylinder(and thus through the anti-lock brake control), so the proper procedure to be used before pushing the piston in is to, using a brake hose pinch clamp, pinch off the hose, open the caliper bleeder valve, use a small diameter hose to direct the expelled fluid into a waste container. Then after pad replacement, pump the brake pedal to reseat the new pads against the rotors, then refill the master cylinder with appropriate fresh fluid.

Lastly, when there is a cold snap, the brake fluid will contract, many times causing the warning light to come on. Then after driving(due to heat under the hood warming the master cylinder), the light may go off, or you may see the light come on briefly when cornering. This is a normal indication of the aforementioned pad wear. Hope this helps.

Check the brake fluid first.is it low or no brake fluid at all.is the brake fluid got dried up or leaked out. Sounds like the power brake booster is bad, that is what the master cylinder is bolted too. There is a rubber hose that has a plastic valve in it were it snaps into the booster, Pull that rubber hose out of the booster and off of the engine, Now the end that you took off the engine. You should be able to **** through the line, but not be able to blow through it. If you can then replace the valve, It is a one way valve.
If that is all right then hook hose back up to the engine and start engine, You should hear a major vacuum leak at the valve end, put you finger over the valve and it should stop making noise and engine should smooth out. If it don't the rubber hose must be leaking or the tube on the engine were the hose hooks to is stoped up. Also check the master cylinder if power booster is replaced. If the brake light is coming and going check the brake light switch. check fig for the internal assembly parts:--

To check engine vacuum, connect a vacuum gauge to the supply hose that runs from the intake manifold to the booster. A low reading (below 16 inches) may indicate a hose leak or obstruction, a blockage in the exhaust system (plugged catalytic converter, crushed pipe, bad muffler, etc.), or a problem in the engine itself (manifold vacuum leak, bad valve, head gasket, etc.).
The condition of the diaphragm inside the booster is also important. If cracked, ruptured or leaking, it won't hold vacuum and can't provide much power assist. Leaks in the master cylinder can allow brake fluid to be siphoned into the booster, accelerating the demise of the diaphragm. So if there's brake fluid inside the vacuum hose, it's a good indication the master cylinder is leaking and needs to be rebuilt or replaced. Wetness around the back of the master cylinder would be another clue to this kind of problem.
To check the vacuum booster, pump the brake pedal with the engine off until you've bled off all the vacuum from the unit. Then hold the pedal down and start the engine. You should feel the pedal depress slightly as engine vacuum enters the booster and pulls on the diaphragm. No change? Then check the vacuum hose connection and engine vacuum. If okay, the problem is in the booster and the booster needs to be replaced.
Vacuum boosters also have an external one-way check valve at the hose inlet that closes when the engine is either shut off or stalls. This traps vacuum inside the booster so it can still provide one or two power assisted stops until the engine is restarted. The valve also helps maintain vacuum when intake vacuum is low (when the engine is under load or is running at wide open throttle). You can check the valve by removing it and trying to blow through it from both sides. It should pass air from the rear but not from the front.
Replacing a vacuum booster is a fairly straight forward job. All you have to do is disconnect it from the brake pedal on the inside and unbolt the master cylinder. The pushrod that runs from the booster into the back of the master cylinder must have the specified amount of play.
You will typically find the power brake booster mounted on the firewall attached to the master cylinder. The master cylinder is connected to the brake pedal.
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The brake fluid level sensor in the master cylinder is stuck in the lower position which completes the circuit to illuminate the light.. Try tapping lightly on the side of the reservoir to loosen it. If that does not help, you will need to replace the level sensor.
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