Thread: HEVAC versus Blend motor curiosity

Hi, New to this forum, so training wheels still on. I own a 2001 P38 in Epsom Green/LightStone in super excellent condition. Totally original.

Have a curious problem with the LH Blend Motor. Did all my research and then decided to take the plunge with inspecting the LH temperature servo (Blend motor). I have never done this before.

I have the standard problem of only blowing cold air on the LH side - which is kind of OK for Brisbane, but we are heading into Winter 2024. Anyway, I successfully pulled out the dash and inspected the Blend Motor. All looking good. Took it apart, decided to clean and apply a little bit of silicone grease. All wheels aligned, arrows pointing to each other - all looking good. No breakages. I then got hold of C1597 connector and applied a 9V bolt battery to the pins for the LH temperature servo (Black and Brown wires). The rotor arm (attached to the LH temperature servo) went backwards and forwards beautifully through the FULL range. I thought "Great"! I then attached the HEVAC to test it using the screen buttons. I began at LO, then as I pressed the button for each Celsius degree, the little rotor arm would move up a notch. But the rotor arm would stop at 20 degrees. The HEVAC screen would keep going up until HI, but the rotor arm would not go past 20 Degrees (which is roughly vertical) or midway through the full range. My question is - do i have a problem or has the HEVAC decided to apply a limit (of 20 degrees) until the Heater core is activated or something else is activated?? I am loathe to reassemble the dash until I am certain I have fixed the problem. Lastly, I don't have the cheque book icon up on the HEVAC. I have not started the car throughout this. I did all these tests with just the ignition on.

Thanks in advance for any advice. Any and all advice is appreciated.

Hope to make some contributions in the coming months.

Thank you. Gives me confidence that the Hevac has this all under control. I will try that little test as well.