Put a PWM on my A/C blower motor

[ULTM8Z]

https://nastyz28.com/threads/more-a-c-blower-speeds.352137/

The thread kinda meanders a bit through the "R&D" I had to do to get to the end result. But I didn't want to retype it all here...

If you don't already have a rotary switch, you'd have to convert to one. I had already converted to a rotary 3-speed switch, so it greatly simplified this upgrade.

But like I said in that thread, it feels like a 21st century A/C system now.

Being in SoCal, I pretty much never run the heater, so I took it off a long time ago, so no heat/cold mixing. A/C is either on or off at full cold.

https://static1.pt-content.com/images/noimg.gif

[Mr Nick]

One of your posts mentioned it's too cold even at low fan speeds, and you have to turn the system off/on to prevent freezing yourself.

Does your system not have a temp control that cycles the compressor off/on?

[ULTM8Z]

It's an old system... from around 2008. Pretty much 100% mechanical (no ECU's or anything like that on the more modern systems).

The vent temperature is normal (~38°F), just that too much cold air is coming out at times.

[Mr Nick]

Got it, thanks. I am looking to install the Vintage Air under dash Heritage unit in my Cutlass, which will cycle the compressor depending on selected temp. I didn't know the older units were all or nothing.

Anyway, cool project and thanks for sharing.

[dontlifttoshift]

Nice job on the PWM control.

Quick question, is the thermostat, the one with the capillary tube in the evap case, not adjustable? I only ask because I never saw one that wasn't.