The Stovebolt Site Forums The Shop Area The Electrical Bay 2 and 3 prong flashers

What is the difference between a 2 and a 3 prong flasher? My new turn signal switch recommends the three prong flasher but my fuse block has a nice new 2 prong flasher.

A 2 prong flasher is switched in series with the turn lights, and interrupts the circuit to produce "blinking". The three prong flasher does the same except an extra contact is made available to feed an indicator light on the switch.

Thanks truckernix. Would there be any problems connecting the two wires from the switch for both the external lights and the ones on the switch?

I don't know how your switch is wired but if it is meant to use a three wire flasher, than you probably don't have a choice. I am going to go look at the diagram for my new flasher.

Ok, so I took a look at my diagram and mine can use the 2 prong or 3 prong flasher. Now, with a 3 prong flasher, the indicator on the switch is fed from the third prong. If one of your external bulbs burns out, you will notice an immediate change in speed or failure to flash at all. This tells you that you have a problem.

With the two prong flasher, the indicator bulb is in parallel with the turning lights and if one of the turning bulbs burns out, you may not notice any change in the flashing rate. That would be my guess as to why the three prong is preferred.