It has been my experience that when the blinker comes on but the lights don't blink there is one or more bulbs burned out. If that is not the case check the flasher.
cheack the wireing
The tail lights are on a separate wiring than the blinker/brake lights. Look for a blown fuse or a broken/loose wire.
change the bulb
Someone is pulling your leg. There is no such thing as blinker fluid! I like to dilute the blinker fluid 50/50 with water. It makes the fluid last longer and the lights flash much brighter....... :)
Probably Flasher
on blinker switch
Press both blinker directions at the same time.
emergency blinker
Take the whole lens out
Most blinker circuits do not flash if one bulb is burned out. If the bulbs are all OK then the flasher is probably bad.
whats the color circuit for the blinkers an break lights?
when you flip your blinker on, a relay in the circuit is activated which turns the light on and off. also, the front blinker and rear blinker usually alternate in turning off and on, so when the back is on, the front will be off, and reverse.. that's why when a bulb is out, the clicking sound in the vehicle goes faster than when both are in working order.