I cannot get my turn signals working. I have two flasher units(one new) and neither works. I attempted to test the flasher unit by removing it from the three prong plug and attaching a hot lead to the input side and a test light to the output side. The test light, 'lights up', but does not flash. Is this a valid test, or is the test light to small of a resistive load to cause the thermal flashing unit to cycle on and off?

Originally posted by ED1966SS:
I cannot get my turn signals working. I have two flasher units(one new) and neither works. I attempted to test the flasher unit by removing it from the three prong plug and attaching a hot lead to the input side and a test light to the output side. The test light, 'lights up', but does not flash. Is this a valid test, or is the test light to small of a resistive load to cause the thermal flashing unit to cycle on and off? You may be right. The more current, larger amp bulbs or more bulbs, will cause the blinkers to flash at a faster rate. The current flow causes the the bi-metal contacts to heat up then open, then they cool down and close then repeat. If there is not enough current then the contacts won't heat up and open.

I've found that the heavy duty camper special or the extra loud flasher cans don't work well in older cars. Not enough bulbs to trip them. The cheaper $3.00 replacement units, from one of the chain auto stores, seem to work the best.

Thanks, I used an old headlight and the flasher unit tested ok. Appearently the little test light didn't draw enough amps to trigger the flasher unit.