Front blower motor intermittent, delayed

The initial problem experienced was the blower motor completely going out, with no reaction to manually setting fan speed.

First steps my mechanic tried was to remove the blower motor and supply power to it, after which it came on with no issue.

After messing with the blower motor, it began working again, but delayed. My mechanic and I suspected the resistor as a result. We replaced it with an after market resistor. It worked on "cold", but response was always delayed. E.G. Change the speed, it would be a 1-2 second delayed. The next day I had to put the heat on, and the blower motor wouldn't engage at all.

From here, my mechanic suspected a bad resistor, so we replaced it with an OEM resistor. After swapping out the resistor, it worked for about 1-2 days, then cut out completely. We also tried a new relay at this time. The behavior exhibited the same with a new relay, the same with the original relay.

My mechanic pulled it, tested it, pulled the blower motor, tested it, put everything back, and it began working again. However, with a twist. It would work so long as we didn't press "off", or "auto", and stuck to just changing temp/fan speed. If you started using off/auto, or used too much manual settings, it would cut off completely, but now turning off the car and back on would restore functionality, until you use it too much, then it goes out.

Today, it wouldn't even come on when I started the car, but all of a sudden, 10 mins into the car ride, the blower motor kicked on.

The only other odd tidbit of information that I'm not sure is related, one of the volume buttons on the steering wheel, if I use (up), will never stop turning up the volume until I restart the car. It's been doing that for 2 years, just stopped using it.

Thoughts? We're at a loss here.