Turn Signal Flasher: Description and Operation

Fig.3 Combination Flasher:

COMBINATION FLASHER
The combination flasher is located under the instrument panel just outboard of the steering column opening. The combination flasher is a smart relay that functions as both the turn signal system and the hazard warning system flasher. The combination flasher contains active electronic Integrated Circuitry (IC) elements. This flasher is designed to handle the current flow requirements of the factory-installed lighting. If supplemental lighting is added to the turn signal lamp circuits, such as when towing a trailer with lights, the combination flasher will automatically try to compensate to keep the flash rate the same.

The combination flasher cannot be repaired or adjusted and, if faulty or damaged, it must be replaced.

The combination flasher controls the following inputs and outputs: fused B(+), fused ignition switch output, right turn signal sense, left turn signal sense, hazard flasher signal, brake lamp switch output, and two outputs each for the right and left turn signal circuits. Constant battery voltage is supplied to the flasher so that it can perform the hazard warning function, and ignition switched battery voltage is supplied for the turn signal function. The Integrated Circuit (IC) within the combination flasher contains the logic that controls the flasher operation and the flash rate. The IC receives separate sense ground inputs from the multi-function switch for the hazard flasher, right turn signal, and left turn signal. A special design feature of the combination flasher allows it to "sense" that a turn signal circuit or bulb is not operating, and provide the driver an indication of the condition by flashing the remaining bulbs in the affected circuit at a higher rate.

If the combination flasher is believed to be faulty test the turn signal and hazard warning system. Then replace the combination flasher with a known good unit to confirm system operation. (Refer to LAMPS/LIGHTING - EXTERIOR/ TURN SIGNAL & HAZARD WARNING SYSTEM - DIAGNOSIS AND TESTING).