Black Box Coolant output

Hi I'm using an 110v air pump for air assist on my laser. I would like to control it using M8/M9 from the coolant output. I installed one of these.
https://www.amazon.com/gp/product/B07W5YQNL9/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
Blackbox will switch the LED on the 24v side no problem, passing as a normal switch the hot from a to b, issue a M8 nothing until I touch a DVM across the A to B then the air pump starts up, on a M9 shuts it off. any clue what I'm missing?

 

so a 24v coil Mechanical should work then?

 

I don't think the 1/4w's in my spares bin will be big enough

 

Thanks, the 100k did it.