Usually non-blinking is due to one of the bulbs burned out.Re-check all of them on that side. Try swapping some bulbs around.
Could be the flasher, but try the bulb swap first. Make sure the tail lights are getting a good ground to the housing. (grind them back and forth against the housing a couple of times each)
Dash blinker not working is probably a contact in the instrument panel. My '68 has an intermittent dash blinker, but it doesn't seem to affect all the other bulbs in the series.
I used to be indecisive. Now I'm not sure. I feel like I am diagonally parked in a parallel universe. 1968 400 convertible (Scarlet) 1976 T/A - 455 LE (No Burt) 1976 T/A New baby, starting full restoration. 1968 350 - 4 speed 'vert - 400 clone (the Beast!) 1968 350 convertible - Wife's car now- 400 clone (Aleutian Blue) (Blue Angel) 2008 Durango - DD 2008 GXP - New one from NH is AWESOME! 2017 Durango Citadel - Modern is nice! HEMI is amazing! 1998 Silverado Z71 - Father-daughter project 1968 400 coupe - R/A clone (Blue Pearl) (sold) 1967 326 convertible - Sold 1980 T/A SE Bandit - Sold
I agree with 68tpls400. Check all those things mentioned. I've had similar problems in lots of older vehicles I've owned. It was almost always was one of those ideas. Pretty easy to check. I also like to put dielectric grease in all my bulb sockets and connections, helps to avoid those problems.
Taillight housing were bead blasted and have good grounds. All the Tail lights work great. All wiring harnesses are new. All the bulbs are new in the dash New printed circuit for the Ralley gauges and I tested the grounding. I may need to pull it again and double check thoes connections. I never checked the flashers.
I suspect the steering column as I painted it and I'm wondering if overspray is keeping the contacts from working.
I was reading the horror stories in the archives. I see Vicky recommended using a test light at the fuse panel. This seems like the most basic check I can do.
Do I just put the light on the flasher fuse and the other side to ground?