Hi Brian! I've attached a close up image of what wires should be going into and coming out of your blower motor. From this information, we see that the wires are dark blue (DB) and dark blue with a yellow stripe (DB/YL). On the regular image, you can trace back that dark blue wire and see that it gets power from the Blower Motor Relay when it it energized.
So the DB wire should have power when the blower motor is supposed to be on.
Now, the Dark Blue and Yellow wire may not have zero volts because it doesn't go directly to a ground, it goes to the blower motor resistor.
So, your first step would be to go directly to your blower motor and check for voltage on the dark blue wire, with the blowers on. Then check for voltage on the dark blue and yellow wire but see if it changes when you switch between high, med-hi, med-low, and low.
If you have voltage on the dark blue wire, then it is getting power, which is good. If there isn't power on the dark blue and yellow wire, then it could be your resistor, but let's not jump too far ahead, I'm also going to add links to some articles that will be helpful. Keep track of what you find so you can reference it later.
I think the latter half of this article on trouble shooting an AC system will be helpful to you, or at least the last half since you have had a mechanic do a free AC check.
https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak
This one is about how to test wiring.
https://www.2carpros.com/articles/how-to-check-wiring
And just one more, for good measure, is a troubleshooting guide for what to do when you are not getting air coming out of your vents.
https://www.2carpros.com/articles/low-or-no-air-flow-from-vents
Images (Click to enlarge)
May 29, 2019 at 4:57 PM
