With 4-way flashers, some older vehicles were made to work this way. It allows the brake lights, when you're slowing and stopping, to have priority over the the 4-way, emergency flashers.
If you're talking only about the turn signal flasher, then, you have a problem. Does this happen with the turn signal lever on left, right, or both?
It sounds like the wiring is grounded somewhere.
The easiest thing to check first, are all of the lamps within the lense covers. Drop the tailgate, and you'll find some screws that will give you access. Look at the filaments, and glass, for a bad bulb.
If all your bulbs are good, I'd recommend taking it to the shop. Wiring problems are difficult to find. Did you have any recent work done on it, just before this started happening?
It has a flasher relay for the signals only.
Probably the turn signal flasher
change the fuse if not replace flasher
The flasher unit is behind kick panel between the steering colume and emergency brake release cliped to its own hanger. It's a small black box measuring about 1.5"by 3"and it controls both turn signals and emergency flashers.
On the 1979 B200 Sportsman V8 if the brake pedal makes all signal lights come on and hazards and flashers do not work on their own, it could be the flasher, but the culprit could also be a burned out bulb or a short in the wiring.
i can not locate the flasher fuse for my 1999 dodge intrepid. pep boys were NO help in locateing it. Turn signal fuse is fuse is slot #9 (driver side fuse panel). There is another fuse in the engine compartment large 20 amp fuse. Flasher is located above brake pedal to the left.
sound like you have a bad ground or a short within the electical system
Check Flasher and/or switch
The 1999 Dodge Avenger signal flasher relay switch is located beneath the drivers side dashboard. The signal flasher relay switch will be between the gas pedal and the brake pedal.
* Burned out bulbs * Defective lamp socket(s) * Broken wire between flasher/switches and actual lamps themselves
A short would blow a fuse. I would check the flasher which is under the eash on the drivers side. The emergency flasher is different from the turn signal flasher.
Turn signals use a relay or 'flasher' which is usually located on or near the column under the dash. Brake lights get their power thru the brake light switch on or near your brake pedal under the dash; check it with a 12v circuit tester.