Front signal come on, but will not flash

Hello and welcome to 2CarPros. So neither one flashes regardless of the switch position, but they come on. Do they come on together? IE you turn on the left signal and both light up or are they correct in terms of right and left? Do they look like they are on full brightness or dim? Are they the correct bulb? Do they come on when you turn on the parking lights?
Looking at the wiring diagram it's a simple system. The front bulbs are in parallel with the rears, they should emulate whatever those do. Even a bad ground should only effect one light as they are split.