Directional signal rapidly blinking

Thank you for your response. So was the outcome of this problem that you have seen before? Thank you. I will check out the fuses all the way around. As mentioned this is a "conversion van" we are talking about.

If a fuse is blown would the electronics downstream of the fuse not be working? Am I missing something?

I do not see where they cyclops brake light center read above tailgate doors, hooks into here. Do you?

Update: Did in fact find a fuse box under the hood. All fuses check out okay with the ignition on and off. Checked the fuse box inside under the dash all but #8 labeled "crank" and number 15 labeled "Illum" both 10A fuses, worked fine switched them out to new fuses, still nothing. Tried all again with both the ignition on and off. No luck.

Another problem I have which I do not know if it is associated or not. My service engine light is on, Said both downstream O2 sensors needed replacement. Changed both of them out, Check engine light came back on. Diagnostic says no activity in left sensor. I am assuming it is not getting any power to it. I would not even know where to start with that. Also, when I shift from park to neutral, the voltage meter does a quick spike and again after driving for a second or two. I have hobgoblins. But still no solution to the initial problem. Right side directional problem as stated. Wondering if everything is tied in?

Ken. The question posed was, can all the electrical problems be tied together somehow with a common problem or short?

No, did not replace the flasher because the hazards work fine and the center brake light works with no problems either. So if it is not broke, do not fix it. So if all the different electrical problems do not have a common source then I have to go back to the blinker issue and the fact that the entire tail light harness was replaced and the common problem with the two harnesses is of one bulb in the harness burning bright, one burning dim and a rapidly blinking directional. All new bulbs. Grounds cleaned. I have resolved to pulling the panels in the interior and tracing the conduit back to the source looking for something exposed heading towards the power source. Unless there is some sort of junction box I can go directly to. Do you not just love electrical problems. It is the principal of it all to me now, lol.

Yes, this I know, but where do you start? Is there a diagram that actually shows where on the vehicle the harness conduit is run on the body?

What "switch" do you specifically speak of? So I noticed today. I have the same bright bulb/dim bulb happening in the front directional/running light. So identical problems in both the rear tail light and front directional, both right side.

Are you speaking of the hazard light switch located on the top of the steering column that turns the hazard light on and off?