2001 Toyota Prius A/C

I have wired a/c direct - so I have cold air. What I need is easy way to keep motor running when I am at a stop (Prius cuts off motor). If I press a/c switch it does make motor come on for short time, but as soon as computer makes switch blink it cuts motor off.
I know replacing the sensor on compressor will be done - but I don't have equipment to evacuate a/c, so for now just need to know where to do momentary contact switch to kick in motor when at a stop. Preferrably someplace that won't harm it :)
I know many things tell it to run motor.
I'll donate $10. Please help.


Thanks,
Jason