98 nissan altima front left blinker does not work when headlights are on, works when headlights are off but blinks rapidly ,left rear blinker works when headlights are on or off but blinks rapidly also

Have you installed any LED light bulbs? Sometimes the low current draw of these bulbs makes the controller think a bulb is out, which in older cars would cause the turn signal to blink rapidly. You may try replacing any LED bulb with a standard bulb.
In your car, the speed is controlled by the BCM. So it could be that your BCM is faulty.

check the ground wires to the rear lights sometimes the head lights will provide backfeed ground when off but cannot when on this would explain the rapid flash

REPLACE THE TURN SIGNAL BULB THAT DONT BLINK.MOST OF THE TIME IT IS THE ONE NEED REPLACING.

check both bulbs front and rear. may have bad contact or replace both bulbs and see if that doesn't fix your problem

Sounds like wrong bulbs in some sockets

if it happens on both side you need to change out your flasher relay, normally located in the fues box or on the underside of the dash, just listen for the tick tick noise and you will find it

Usually a fast turn signal means that there is a light out. You should probably check all of your lights, including back-up lights, and turn signals. If there is one out then replacing the burnt out bulb should fix the problem.

hi usurally when that happens that means you have a bad bulb or bad wiring.

The problem could be the wiring connecting to the lights, you need to check them for bare wires. Look them through for any metal hanging out of the rubber insulation. You may need to get new wiring.

this sounds like a ground issue........ did u replace with new bulbs? not all bad bulbs show" burned " out filiments good luck jimmy