My brakes seem to fail when the ac is on - 2001 Mazda MX-5 Miata

brake lamp at rear of car?, or in dash, we need to know what lamp where.
brake on its OWN not on.
will the brakes are on. if the car stops by self.
brakes do fail on all vehicles made , and for ever.
that is why we do service on cars, to prevent them from failing
while you drive , called safety.
you need to get car serviced, i can tell you have never had brake issues before.

my guess is the dash cluster brake waring light glowed and you didnt read the operators guide, it says, do not drive car.
get it serviced.
the brakes have failed.

I believe your A/C idle up valve may have failed. They do this when hot, but test OK when cold. See here p228

http://www.turboninjas.com/camry/eg1.pdf

It is unlikely that the replacement of the water pump and AC failing are related, however ensure that the V belt is correctly positioned and under tension. The AC pulley should be spinning continuously by the V belt. The AC compressor is engaged by an electrically operated clutch within/behind the pulley wheel. If the pulley wheel is not spinning but the belt is sliding over it then you have a seized AC compressor and this will most probably need replacing. If the wheel is spinning but the AC compressor is not working (no cooling) then it is the clutch that is not engaging. This could be due to a worn clutch, failed clutch actuator, broken electrical connection, failed relay, broken fuse a failed interior thermostat (the car thinks that the 'set' temperature has been reached and so switches the AC off). To check, put the AC on the lowest setting and test the voltage at the AC compressor connection. If voltage is being supplied it is likely to be a failed AC clutch. There are lots of AC clutch repair videos on youtube and these should be a great help.

Thats the Traction Control System...indicating one wheel is spinning at a different speed than another.

It just so happens that the ABS Braking System ties into this as well.

I'd check the brake fluid level first...then the fluid level switch (some are in the cap and some are in the brake master cylinder.)

Hope this helps...

Check another vac source in/around engine. When you load engine with brake booster, then lower vac pressure w/Up idle, it's amplifying another vac source that might be weak.

Your brakes may be dragging due to not releasing properly. Suggest that you take the car to a brake shop and have them inspect the entire system. Good luck!

Hi:
All modern cars have a dual brake system, this way if you would happen to spring a leak in your rear brakes, your front brakes still work. When one system fails, you get a brake light. In your case, the first place to start your troubleshooting is to check the fluid level in the brake reservoir. If either the front or back of the reservoir is empty, you have a leak. If both are still full, the most likely problem is your master cylinder failing. If you think you have a leak, look at the inside edges of all 4 wheels, and look for signs of brake fluid .

replace the switch you broke

These problems do not seem to be related at all. The cause of the warm ac air could be several things from a low refrigerant charge to a plugged condensor fins to the compressor clutch not kicking in. You just have to follow a systematic approach when diagnosing these problems.

i would check it,seems u have an open circuit,switch not working,broken wire or corroded elect.connector.