Manual fan mode (Cool/Max) reverts to macOS auto control after a few minutes — M4 MacBook Pro

[jacksgithubacct]

Environment

• Machine: M4 MacBook Pro
• App: Mole (Mac app)
• Installed via: Homebrew cask (caskhub)

Description

When I select a manual fan mode (either Cool or Max), it works for a few minutes and then the fans appear to hand back to the Mac's automatic (SMC) control. The RPM readout itself looks accurate.

The problem is that the UI still shows Cool/Max as selected even though manual control has effectively stopped — so the displayed state no longer matches what the fans are actually doing.

Expected

Once Cool or Max is selected, the manual fan target should stay applied until I change it — or, if manual control genuinely can't be held, the UI should reflect that it's fallen back to auto.

Actual

• Cool/Max applies correctly for a few minutes
• Fans revert to (apparent) macOS auto control
• UI still shows Cool/Max as the active selection
• RPM display appears accurate throughout

[tw93]

@jacksgithubacct thanks for the precise report. The detail that the UI kept showing Cool/Max while the fans were audibly back on the automatic curve is exactly what pinned this down.

You were right on both counts. Mole applied a manual preset as a single SMC write and never verified it afterwards, so when macOS quietly reclaimed fan control a few minutes in, nothing noticed and the UI kept displaying a hold that no longer existed. Preview build 172 fixes this: while Cool or Max is active, Mole verifies the actual fan speed against the held target every 30 seconds, silently re-applies the preset when the system has taken the fans back, and if manual control genuinely cannot be held it returns to Auto with a note saying so, instead of leaving the selection lying.

The fix is live in the current Preview: https://mole.fit/Mole-preview.dmg (build 172). I cannot reproduce the few-minutes revert on my own hardware, so your M4 is the real test bench: if you can run Cool or Max under the same conditions again, I would love to hear whether the hold now survives. Closing as completed, and please reopen if it still slips back to automatic control on your machine.

[jacksgithubacct]

@tw93 I have tested the preview and noticed that it will run for a few minutes, then go back to 0RPM, and then back to ~3500RPM after maybe 30 seconds of 0RPM.

[tw93]

@jacksgithubacct Sorry, you tested this and reported back and then nobody answered for three weeks. That one is on me.

Your screenshot is the original problem rather than a fixed version of it: the tile reads Holding around 60% while the fan reads 0 RPM and the CPU sits at 80 degrees. The verify loop does haul it back, but a 30 second window where the caption still claims a hold it is not delivering is exactly the mismatch you filed this for, so I am reopening it.

Before changing anything I need to know which of two things is happening, because the fix is different for each and I have no M4 here to reproduce it on. During one of those 0 RPM stretches, is the machine actually silent, or can you still hear the fan running? Audible means the fan never stopped and what is broken is the reading Mole gets back from the SMC. Silent means the hold is genuinely being dropped and something is handing control back to macOS.

Tell me which one and I will work from there.