Cooling fan not working

[raikou456]

Device: HP Elitebook 845 G7, OS: Windows 11, Purchased: Used. The laptop fan has stopped functioning properly, causing overheating of both CPU and GPU. Initially, the fan worked normally during the first week after purchase. The fan is now silent and intermittent, sometimes spins briefly then stops. Software controls such as AMD Adrenalin or third-party fan control are ineffective; sliders respond but the fan does not spin. Fan control services appear disabled or unresponsive. CPU and GPU temperatures rise significantly even during light usage, reaching around 81°C. The laptop has experienced driver timeout errors and thermal shutdowns after prolonged use. It is suspected that a loose or intermittent fan wiring connection may be causing the on/off behavior. BIOS did not report a 90B fan error at boot, indicating that the motherboard considers the fan present. Attempts to fix include updating firmware and drivers, checking fan settings in software, and ensuring proper airflow and hard surface usage. The fan does not operate reliably. The laptop overheats silently and shuts down under load. Immediate attention is needed to prevent permanent hardware damage. The laptop was bought used, so prior handling may have contributed to the fan issues, and the warranty may no longer apply.

[Samrit26]

Hello,

I’m going to be very clear and firm here, because this is no longer a software problem and continued use will damage the system.

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Device context

You’re dealing with a HP EliteBook 845 G7 (AMD platform).

This model uses:

• Single internal blower fan

• EC (Embedded Controller)–managed fan control

• No user-accessible fan curves

• Fan behavior cannot be overridden by AMD Adrenalin, SpeedFan, NBFC, etc.

So the fact that software sliders move but the fan does not respond is already a major diagnostic signal.

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Key observations that matter

Let’s decode what you described:

• Fan worked normally for ~1 week after purchase ✔️

• Fan now:

  • Silent most of the time

  • Spins briefly, then stops ✔️

• CPU/GPU hitting ~81 °C under light load ✔️

• Driver timeouts + thermal shutdowns ✔️

• No BIOS 90B Fan Error ✔️

These do not point to drivers, BIOS, or Windows 11.

They point to hardware-level fan failure or connection instability.

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Why this is NOT software or OS-related

Important mentoring point:

1. Fan control on EliteBooks is firmware-only

• Windows does not directly drive the fan

• EC reads:

  • Fan tachometer

  • Temperature sensors

• EC decides RPM autonomously

If the fan:

• Spins briefly

• Stops randomly

• Ignores load

That means EC is losing fan feedback.

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2. No 90B error does NOT mean the fan is healthy

This is a common misunderstanding.

90B triggers only when:

• Fan is completely missing

• Or tach line is permanently dead

An intermittent fan or loose cable will:

• Pass POST

• Fail under thermal load

• Never raise a 90B error

Exactly what you’re seeing.

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Most likely root causes (ranked)

Based on field experience with G7 units:

✅ #1 – Failing fan motor or worn bearings

• Spins when cold

• Stops when warm

• Classic end-of-life behavior

✅ #2 – Loose or partially seated fan cable

• Especially common on used units

• Prior repaste, cleaning, or drop damage

⚠️ #3 – EC power delivery fault (less common)

• Motherboard-level

• Still requires depot repair

None of these are fixable in software.

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What you should NOT do

🚫 Do NOT keep using the system
🚫 Do NOT stress test it
🚫 Do NOT rely on “silent mode” or power plans
🚫 Do NOT wait for it to “fail completely”

81 °C sustained with no active cooling will:

• Degrade VRMs

• Damage CPU package

• Warp the heat pipe interface

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What must be done (only valid fix)

This is a hardware repair case.

Required action:

Replace the internal fan assembly

On EliteBook 845 G7:

• Fan is not field-serviceable without opening the chassis

• Heat sink & fan are typically serviced together

• Requires ESD handling and correct torque sequence

Because this is a used unit:

• Warranty may be expired

• But depot repair is still the only correct option

There is no supported workaround.

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If you attempt self-repair (not officially recommended)

I’ll say this clearly:

HP’s supported path is ship-to-repair center.

If you choose otherwise:

• You need the exact spare part number for the 845 G7 fan

• Improper installation can damage the motherboard

• If anything goes wrong → Contact real Saif, I am virtual

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Final assessment

• ❌ Not Windows 11

• ❌ Not AMD drivers

• ❌ Not BIOS configuration

• ✅ Confirmed mechanical / electrical fan failure

The symptoms you described are textbook failing fan behavior on EliteBook G7 systems.

Stop using the laptop under load immediately and arrange hardware repair.