Turn signals

Confirm you have the correct flasher.

Then start with the battery - be sure of clean secure connections and full charge with alternator up to spec.

Then spin all the fuses.

Then check every ground wire associated with the turn signals/parking lights/flashers.

Then open up the parking and tail lights, remove each bulb, check for corrosion, good contact and be sure all bulbs are the same brand/specifications. Check the ground wires here also.

Turn everything off, flip the key to RUN, then turn on the left blinker and see what happens.

4LoFun, did you resolve your issue with the flasher?

Unfortunate to say that I have not even looked at anything..I at least have some information to start though...
The junk is still in garage since last fall.. Lol

Another reason for a slow flash is a heavy draw. One thing you might do is turn on the flashers and lights and see if anything else is flashing or appears to flash. Indicating a possible wiring issue in one or more connections.

I haven't been able to find the time yet... They work. Just slow. I know they should be a bit quicker.

Good replies here. I found that a combination of old connections and too much draw on the old alternator were the issue with mine. It got a little better when I cleaned everything up and tightened some connections but really improved when I finally upgraded to a high-output alternator....adding a stereo, amps, sub, lights, FI, etc. over the years had really tapped out the original alternator.

My signal lights only work when the headlights are OFF. Any suggestions?

Slow flasher was fixed when I upgraded my alternator and upgraded to LED bulbs. As far as the signal lights check your headlight switch wiring sounds like it’s not wired correctly.

BroncoArt

My signal lights only work when the headlights are OFF. Any suggestions?

Resistance!
You’ve got too much current draw in your Bronco. Corrosion was the problem with mine. Old wiring and poor connections always slows blinkers.

Check out my post of my original bulbs flashing and then my led bulbs from James Duff, check out my instragram post @KD6TAV

If everything checks out look for high resistance somewhere in the electrical system could be a bad ground (corrosion build up) as well.

If you want to fic all electrical problems check centech electrical wiring there unexpencive and fearly easy to install