Turn signal indicators or blinkers as they are called work in a specific manner which is dictated by the turn signal bulb and circuit resistance.
A BCM or flasher unit is incorporated into the turn signal system and is used to momentarily interrupt the circuit to create the blinking action. This system works on the resistance normally present in the lighting system.
On older vehicles a turn signal flasher is used to control the blinking intervals while newer systems use a BCM (body control module). When the system resistance changes either by a missing or burnt out bulb, blown fuse or corroded connection the blinkers will cycle more rapidly.
Inspect both the front and rear of the vehicle to identify a directional signal
bulb failure, remove the lens or gain access to the rear of the lens and
remove the turn signal light bulb.
Sometimes the bulb can be good and electrical corrosion is the problem. When
the bulb is removed, inspect the electrical connector terminal condition, if a slight
amount of corrosion is present it can be repaired using electrical connector cleaner
and a small wire brush or Exacto knife. If excessive corrosion is present the connector
must be replaced as in the example below.
If all four turn signals are blinking quickly
check the fuses on the BCM or fuse
panel, if your vehicle has a turn signal flasher unit, replace it. If exact fuse
or BCM locations or procedures are needed you can ask our
experts to supply you with the information (free), or consult an online resource
such as AllData DIY (pay).
If everything seems to be working correctly a CAN scan (Controller Area Network) can be performed which can help pinpoint the problem as in a BCM failure or a TIPM issue in Jeep and Chrysler products.
Our certified technicians are ready to answer car repair questions for free. We hope you saved money and learned from this guide. We are creating a full set of car repair guides. Please subscribe to our 2CarPros YouTube channel and check back often for new videos which are uploaded regularly.