If you have too much or too little gas in the system will this cause sensors to stop the clutch from engaging on the compressor???? here's the story so far ... i bought one of those gas topup kits off ebay CAR AIR CONDITIONING RECHARGE KIT GAUGE & LEAK STOPPER :: DIY Products :: Autokool Ltd where you get the guage to check the pressure.... we did my dads car first an A4 and when we plugged on the guage it said the pressure was in the green and fine but when we started the engine this pressure dropped down very low so we topped it up with the aircon running and all is fine on his.... Now onto my A3, when i plug the guage on it says my pressure is in the red and too high.... but the clutch won't engage for me to get a reading whilst it's running , is this because of the high pressure ?? every now and then the clutch will engage but timing it to work when i have the guage connected seems impossible but it does prove that the compressor and clutch do work... all be it when they want to.... any advice guys ?? maybe vent off a bit of pressure ??