ok my brother is having a strange problem with his a/c in his 94 eg hatch

if you start the car in the morning or anytime at night a/c works perfect cold as a new car but if you leave the car out in the sun the compressor will not kick on.
If you park it under a tree with the windows cracked it will work fine and you are able to roll up the windows and be fine but if you let it sit and the inside of the car gets too hot the compressor will not kick on almost like theres some kinda switch under the dash or something. At first i thought it was the dash just being so hott but after some trial and error we figured the compressor just doesnt kick on but in the afternoon it will and its ice cold could the a/c controlls be broken somehow with too much heat inside the car thanks in advance for any help