A/C intermittently blowing hot air?

It sounds like the system is low on charge. here is a video and a guide to help us fix the problem:

https://youtu.be/4UjfQKvrB6Y

and

https://youtu.be/uZrQCGwXfek

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak



Please go over these guides and get back to us.

so, when the A/C blows hot air the clutch is not engaged but the fan is on and there is voltage going to the magnetic coil. Is it a bad coil?

It could be but to confirm let's check for power at the compressor when the system is on, and the compressor is not working.

This guide can help:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Test the wire going to the compressor and let me know.

When the system is on and the compressor is Not working there is power 12v I used a test light to check.

Okay, you have found the problem; the compressor coil is bad and needs to be replaced. You may need to remove the compressor which at this time you may consider replacing it as a whole unit. Here is how the job is done step by step and I have included instructions in the images below for your car.

https://www.2carpros.com/articles/comprehensive-guide-how-to-replace-an-ac-compressor-clutch-on-a-car

You will need to follow this video:

https://youtu.be/4EqdrBVb0sY

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.