Coleman Mach thermostat ticking A/C won't come on

Your description of 'lock up' seems right-on. That's what it seems to do. It makes a noise like it 'wants' to come on and then locks up. Since the heat has abated in my area, I'm going to take a wait/see if any come up on sale! Thanks so much again. I have subscribed. The information you've provided is solid and I'm looking forward to learning more from you.