I need help please I am very handy but I am also completely an ac virgin. After some intense Googling I am here. I have a intertherm Package unit AC I cannot seem to find the exact model number by looking at the website I think it has to be one of these models P7RD, Q5RD, P5RF & Q5RF. Sorry. Anyway the AC stopped working yesterday I have never had any issues with it before. I got it second hand it is about ten years old. I remember the power flickering at some point yesterday but that might have been earlier in the day when it was storming. I know it was working after the storm passed, it may be unrelated. I have electronic thermostat made by Hunter inside it says no AC power. I tested the wires going directly into the ac and they have power so the problem has to be inside the air conditioner or with the thermostat that is in the house?? The thermostat in the house seems to be working fine and is about 6 years old, I reset it same issues. I took off the side panels of the ac and all the wires on the inside look good and well connected nothing looks burnt, worn, or melted. The capacitor looks very good on the out side I have no clue how to test it or even if that is where I should go next, The computer said look at it so I did. Lol. I found a video but realized I could spend my whole life looking at videos I needed professional help. I need to know what to test, how to test it, and where it is. I have pictures of everything. I did not take the last panel off that covers the compressor because it was going to rain but it looked good from what I could see. I will attach pictures any help is greatly appreciated I live in Florida. (What does that switch do in the last picture I could find out anything about it, just out of curiosity I didn't think it was related.)

It's hard to read the wiring diagram but, for starters, look for an automotive type fuse on the circuit board. Do you have a voltmeter & know how to use it?

Sorry I just got home from work I will check for a fuse. I do have a meter and I am just learning how to use it. Thank you for replying!

Since you are just learning to use the meter, I suggest getting a friend who is comfortable in using one to help you. Inside this piece of equipment there are VERY dangerous voltages which can kill you. A lot of the testing required will involve working with live circuits.
I'll be glad to help by telling you what voltages to expect where.

There is not a fuse on the circuit board, I was hoping for a fuse when I opened it up. I do not have anyone to help me I wish I did. I do have an AC guy but cannot call him till Friday (payday). I plan on researching every part you told me to check to find a video to show me how to do it, but I just had no clue what part to start with?

With your meter set to AC Volts, put one lead on each of the terminals where the large red & black wires connect to the contactor (center of the third picture). You should get aprox. 240 volts.

I am sorry I did not reply earlier I really appreciate your help. I really want to learn how to use a meter and will definitely work on it. I did not get an email when you replied to this thread it sent me one today. Weird... I figured you thought I was in over my head which I am sure I was, so I waited. I have a really good AC man he fixed it for only $100.00 dollars, awesome!! He replaced the transformer in the unit and the air was blowing hot set on cool (it wasn't signaling some cycle or something over my head) he replaced the inside Thermostat problem fixed. I still was curious what the switch in the last picture does if you know I meant to ask him but I forgot. Thank you again as a woman who like try and fix stuff it is hard to find help.

Without being able to read the wiring diagram, I have to guess it is a manual reset pressure switch.

Grady, it looks like some sort of dial to me. I have no Idea what it would be for, but it kind of reminds me of a econimizer setting on commercial units (damper open settings, etc.). Most likely there used to be a knob on it and some sort of marking for whatever position the knob was set to? Hard to tell from the pic, but I bet there is a flat spot on that shaft for the knob to fit in only one way. Only reason I think this is because I can see the cam that allows the knob to turn between the 9 o'clock and 3 o'clock positions. Or am I crazy ( no need to answer that last question, pretty sure I already know the answer!).

Good thought Dad. You got me thinking (that's dangerous). I'll bet it's for an old outdoor thermostat, used to shut down the compressor when it's below x degrees outdoors or to lock out the strip heat (or some of it) if it's above x degrees.