Hondata

So i put launch control on a friends car last night and it works fine in always on mode, but when i tried using the A/C switch to run it, it only worked sometime.

You could get ready to launch with the A/C switch on and it would limit it, but if you let off and tried again right away, it would let it free rev. It seemed to work most often if you waited for a bit (30 seconds or so) before trying it again, but we didn't try enough to know if that always worked. Any idea why it doesn't always work correctly when using the A/C switch??

are you using the ac switch input with another switch or are you using the factory ac switch?

if so isnt it only a momentary? i could be wrong.

If you post a datalog and calibration then we can look at the settings and input behavious to see what is wrong.
If you use the AC switch for launch conrol, then you need to re-wire it so that it grounds the ECU AC input without the AC pressure cutout wiring.