the VTEC gets 12V +ve from the ECU when the parameters are satisfied - which are
engine temperature above 70C - taken from CTS
engine speed above 3000 rpm - taken from crank sensor in distributor
throttle opening more than 50% - taken from throttle angle sensor
vehicle speed above 45 km/h - taken from VSS
ECU in closed loop - no CEL condition existant - default drive mode
Honestly you need to either find better technicians or you have really low standards for gurus. btw - unplugging the VTEC solenoid at idle speed should not affect anything at all. If you apply voltage to the pin of the solenoid your engine will balk a bit only as the higher lift cams are phased a bit retarded with longer duration - hence your intake vacuum goes down (MAP goes down). If you unplug the VTEC or even idle control valve the ECU goes to limp mode.
The way I repaired these kind of cars was to remove the wiring and sort it out completely outside the car, then splice the car to the ECU and splice the body wiring to the engine wiring where required (dash lights, A/C signal, temp gauge, alternator etc)
the A/C signal of Honda is given as direct 12V earth to the ECU, the ECU then sends its own signal to the A/C magnet relay and hence also fan relays to start the refrigeration, It passes through the thermostat first then the to ECU, The wire from the ECU is passed first from the low pressure switch and then to the magnet relay - which then goes to the single wire of the compressor.