Never saw a pressure switch like the one pictured on
your bottle. This one is adjustable. Sounds like the pressure switch or relay is bad if it works hooked up directly. Does it only have pressure to it when the bottle is open, or all the time? If its all the time, are you sure the pressure in the bottle is low enough to even turn the heater on? Check and see if you have continuity across the terminals on the switch to make sure it is in the closed position. It should be closed to complete the circuit, and turn the heater on. Just throwing ideas out there. Don't mean any disrespect.

 

Here is the wiring diagram just in case.

 

you know what, I bet that is my problem. No disrespect taken. My bottle was low when i was trying it the last time and I just had it filled. It has a flat head screw where the black *** is. I'll try it again with the bottle full. I'm fairly new to the nitrous game so I'll learning these things as I go

 

that's actually the first diagram I followed but then I ended up changing it because some other diagrams show different and i tried the 2 ways listed above also

 

When I set the adjustment screw I screwed it all the way in

 

 

What brand is the bottle heater, and did you get the pressure switch with it or separate?

 

el cheepo from Amazon, the bottle heater itself works fine. It I disconnected the switch and hook the heater directly to the arm switch it warms fine, and yes they came together

 

While you have the pressure switch off. Check continuity on the two terminals to see if that switch is on. If it's not, the switch is bad, otherwise it should work. If it's off. Try screwing that adjuster out while your checking, to see if it turns on. Just to see if it increases the opposite way. Worth a shot. Unless you have directions saying to screw it in to increase pressure.