Hondata

I recall learning that when A/C is on (OBD1 B-Series) that the ecu had some affects to vtec operation. I can't recall if it was that it briefly turned off the compressor while vtec is active or if it raised the vtec point slightly. I could be imagining this too.

The help file states for the A/C swith:

Activates when grounded. Normal function is to idle the engine up and delay the AC clutch when activated. Can only be used when you do not have AC. Note that if you want to use the AC Switch itself, then you need to alter the vehicle wiring to ground the other side of the AC Switch.

Is the ecu also sending the signal to the a/c clutch to engage? The help file says it "delays" the ac clutch. Does it delay it or engage it, or both?

And is that correct that these are the only affects of the ecu when a/c is active?

AC should have no effect on VTEC activation.

The ECU operates the clutch relay to activate and deactivate the AC depending on the conditions.