Vq heater not working

[lildavo]

Heater hoses seem to not blocked up pulled my heat tap off pushed the arm on to open it up it opens makes a pop noise when it shuts water will flow through it open so don't know if my vac lines are stuffed how do I cheak that coolant is getting past the heater tap only way I throught was hook it up to the water pump side vac line on and run it and see if it opens up with the heater on to let coolant in?

 

[lildavo]

Just did a test so the heater tap isn't letting coolant through unles I physical push the arm in my self then get nice warm heat so take it it's a vac problem I got no idea where these sola lids are that control the vacuum iv had the radio fascia out before hut couldn't see them.