The turn signal and brake light use the same bulb. When you get a fast flash, it is from a reduced electrical load being placed on the flasher unit due to a burned bulb. Replace the bulb and this should fix your problem.
Short to power in the brake light circuit. Most likely, the fault is in the switch itself.
the circuit is broken through the turn signal switch, allowing the light to flash
light is burned out
When any turn signal on a vehicle flashes more rapidly than normal, then that means that a signal light on the side that is blinking is burned out. It could be either the front of back. You should check your signals to see if one is burnt out. The brake however should not affect this - you could have a short.
Check your brake fluid level in the brake master cylinder in your engine compartment when it is low your brake warning light will come on
Usually this a faulty signal light switch. The Signal light switch disconects the brake light on the signaling side and makes it flash.
If you have the same bulb for brake and signal, brake light power needs to be interrupted by the signal lights, The brake circuit has to go through the signal light switch so the problem could be there.
usually means you have a turn signal bulb in the front or rear burnt out.
the bulb for brake and signal lights has two elements. in your case the element for brakes is open and you will have to replace bulb.
On most cars, the brake light and turn signal are the same element in the bulb with two elements in it. The other one is the tail lights. The brake light will often burn out sooner because it is used more and the on off is harder on the element. If you have the front amber running lights, it is almost certainly the bulbs.
Check all fuses. Wait until dark. Park where you could see the glow of the brake lights from inside the truck, were they to illuminate. Press and hold the brake pedal. Wiggle the turn signal switch about for a few seconds. If this causes the brake lights to work or to flicker, replace turn signal switch. Move tilt steering up and down. If this causes the brake lights to work or to flicker, replace turn signal switch. Switch 4-way flash hazard lights on and off a few times. See if that does anything interesting. Check for Body codes.
In many cases, the brake light and the turn signal use the same bulb.