Well...I originally took my car into SUPER VIP for the installation of the HID Kit. Worked ok for a day, then lights flickered and D2S bulbs were fried. Apparently they hooked it up to the harness emittiting power for the old headlight motor. Had a date that evening; so I said screw it..and wired the HID kit to the high beams. I've look at the wiring diagram and it makes no sense unless the old headlamps had a built-in relay for hi/lows
The power to the highs & lows comes from the same connection electrically - they come from the headlight relay which is enabled by the headlight switch regardless of which way the high/low switch is set. The - side for the lows is permanently hard-wired to ground, so low beam comes on with the switch on the stalk. The - side of the high beams is enabled by a relay when the low/high switch is set to high - note that the low beams remain on
when the high beams are selected. The power to the + side of the high & low beams is also connected to the input of the motor controller, which tells the pop-up to open.
If the connections to the motor itself were used it is conceivable that it might almost work - for a while - but the motor voltage reverses when the light goes down as opposed to opens - this would apply reverse power to the ballast/igniter,but Iwould suspect a) they would be reverse power protected & b) if not they would be the parts damged, not the bulbs.
In the cct below I've drawn the current paths - red is power to the high & low beams; blue is the ground for the low beams; purple is the ground for the high beam (though the switch controlled dimmer relay); green is the ground for the light power relay (through the stalk switch) & also for the other dimer relay circuit va the dimmer switch.
So I thinkyour mod works just fine - connecting the power side to either the high or low is identical - the ground is what is switching