Replacing Instrument Cluster bulbs with LEDs - Illumination Detail Question - 67 Barracuda

Sounds like some basic tests might be useful to solve your problems.

1. Do your bulbs light up if you short across the two flasher terminals with the turn signals on? Is they do, your flasher is likely bad or hooked up wrong.

2. Can you hook up your flasher and a bulb in series directly across the battery to see if it flashes?

A lot of chinesium stuff is bad out of the box. Divide and conquer. Check all your parts first to see if they are good.

It is also possible that the two flasher wires are reversed in the flasher connector.