I have a maple chase 4 wire thermostat model #09500 and I have just started using the air conditioner which works through the furnace. I have some trouble making it work so I wanted to test it. How do I determine which wires control the air conditioner?

You have to be careful touching wires together on the thermostat because, if you start and stop the outside unit suddenly you may end up popping the breaker and even the contacts of the breaker due to the enormous surges when the compresor turns on under hig head pressure.

The thermostat usually incorporates a lockout between 2-5 minutes, so that the unit will not turn on unless if has been off for that amount of time.

Rc (or R) to G will turn on the fan.
Rc to Y will turn on the outdoor unit without the inside fan.

So, you really need (Rc/R) to G and Y to operate the AC.