I only see two wires, but it’s clear that correct.
How do you have it illuminated in your hand?
Is the controller turning it on or?
If the blue (-) line going to the controllers ‘wind’ is still on the controller, take it off, then you’ll have 24 volts only to the solenoid with a blue (-) wire free. Take the blue (-) and find a ground, a good ground, at the supply or GND on that connector… You have the complete circuit, sans controller. It will work or it’s broken. If it shows the same symptoms as the dimming when you plug it on the coil then you can probably toss it as it’s an example of poor Chinese craftsmanship.
This is what Dave had suggested a while back
You should be able to physically feel the solenoid move when you apply power.
Pulled one from the junk box. On a 24v supply (no air) it draws 149 ma and the led is the same intensity, connected or not. If that’s not the case with you, toss it
The only other ‘flaky’ thing that can be an issue is the connector itself. I’ve seen it too many times to discount it completely.