Best place for smoke test

[Brickthing]

I am trying to smoke test my vacuum lines and am trying to figure out the best spot to actually input the smoke to do that. The end goal is to find the probable vacuum leak that is forcing my AC to be stuck in defrost. Thanks for the help!

 

[bobbywalter]

whats your test unit equipped with?

i usually push it through from the booster side first and move around from there for specific components ect

 

[Brickthing]

whats your test unit equipped with?

i usually push it through from the booster side first and move around from there for specific components ect

Just a small nozzle. When you say booster where is that on exactly located on the 4.0

 

[bobbywalter]

the big vac line on the brake booster