P0695 Cooling Fan 3 Relay Control Circuit Low

The P0695 – Cooling Fan 3 Relay Control Circuit Low diagnostic trouble code (DTC) indicates that the engine control module has detected lower-than-expected voltage in the control circuit for Cooling Fan 3.

The cooling fan system is responsible for maintaining proper engine temperature and, on many vehicles, assisting the air-conditioning system by cooling the A/C condenser. Depending on the vehicle, Cooling Fan 3 may refer to a third physical fan, a third relay, or a particular fan-speed stage.

P0695 is primarily an electrical circuit fault code. It does not automatically mean that the cooling fan motor has failed.

What Does P0695 Mean?

In simple terms:

The ECU detects that the Cooling Fan 3 relay control circuit voltage is lower than expected.

A simplified system may look like:

ECU → Fan Relay Control → Cooling Fan Relay → Fan Motor → Ground

The ECU monitors the electrical condition of the relay-control circuit.

If the measured voltage falls outside the expected range on the low side, the ECU can store P0695.

The exact voltage threshold depends on the vehicle manufacturer.

What Is Cooling Fan 3?

The term “Cooling Fan 3” is not universal.

Depending on the vehicle, it may represent:

• A third electric cooling fan

• A third cooling-fan relay

• A high-speed fan circuit

• A particular fan-control stage

• A specific output from a fan-control module

For example, one vehicle might use three separate fans, while another might use several relays to create different fan speeds.

Therefore, the vehicle-specific wiring diagram should be used to determine exactly what Fan 3 represents.

What Causes P0695?

Possible causes include:

• Short to ground

• Faulty cooling fan relay

• Damaged relay-control wiring

• Open or high-resistance wiring

• Corroded connector

• Loose terminal

• Faulty cooling fan control module

• Incorrect relay

• Fan motor problem

• ECU driver circuit problem

• Poor electrical connection

• Aftermarket wiring modification

The exact cause must be determined through electrical testing.

Can a Bad Cooling Fan Relay Cause P0695?

Yes.

A faulty relay can cause abnormal voltage in the control circuit.

Possible relay failures include:

• Internal short

• Damaged coil

• Stuck contacts

• Corrosion

• Incorrect relay installation

The relay should be tested according to the manufacturer's specifications before replacement.

Can a Short to Ground Cause P0695?

Yes.

A control wire that is shorted to ground can pull the circuit voltage down.

For example:

Fan relay control wire → Damaged insulation → Ground

This can cause the ECU to detect a low control-circuit voltage.

Look for:

• Chafed insulation

• Pinched wiring

• Melted wires

• Damaged harness

• Incorrect previous repairs

Can an Open Wire Cause P0695?

Potentially.

An open or high-resistance circuit can prevent the relay from being controlled correctly.

Depending on the electrical design and monitoring strategy, this may result in a different fan-control DTC, but P0695 can occur when the ECU detects the control circuit at an unexpectedly low voltage.

Can a Bad ECU Cause P0695?

Yes, but it is not the first thing to suspect.

The ECU may control the cooling-fan relay through an internal electronic driver.

If that driver fails, the relay control circuit may not operate correctly.

However, the following should be tested first:

• Relay

• Wiring

• Connectors

• Power supply

• Ground

• Fan-control module

Only after these components have been verified should an ECU driver problem be considered.

Can a Cooling Fan Control Module Cause P0695?

Yes, depending on the vehicle.

Some vehicles use a dedicated cooling-fan control module instead of a traditional relay-only system.

A fault in the control module can cause:

• Incorrect fan operation

• Low control voltage

• Fan not operating

• Fan operating at the wrong speed

• Multiple cooling-fan DTCs

Symptoms of P0695

Possible symptoms include:

Check Engine Light

The MIL may illuminate when the ECU detects the fault.

Cooling fan not operating

The affected fan or fan stage may fail to activate.

Engine temperature increases

If the affected fan is required for cooling, coolant temperature may rise.

Engine overheating

A severe fan-control problem can eventually cause overheating.

Air-conditioning performance problems

The A/C condenser may not receive adequate airflow at low speeds.

Fan operating at the wrong speed

The cooling system may fail to switch to the required fan stage.

Fan operates intermittently

A poor electrical connection can make the problem appear and disappear.

Can P0695 Cause Overheating?

Yes.

If Cooling Fan 3 is required under high-temperature or high-load conditions, failure of its control circuit can reduce the cooling system's ability to remove heat.

This can lead to:

Fan control failure → Insufficient airflow → Coolant temperature rises → Engine overheating

If the temperature gauge rises above normal, stop driving and investigate the problem.

Can P0695 Cause the Fan Not to Run?

Yes.

If the affected relay or control circuit is responsible for activating the fan, a low control voltage can prevent the fan from operating correctly.

However, whether the fan stops completely depends on the vehicle's fan-control architecture.

Other fan stages may continue operating.

Can P0695 Cause the Fan to Run Continuously?

It can, depending on the system.

Some vehicles activate a fail-safe cooling strategy when the ECU detects a fan-control problem.

As a result, the fan may run:

• Continuously

• At high speed

• After the ignition is switched off

This behavior is not universal.

Can P0695 Affect the Air Conditioner?

Yes.

Cooling fans are important for removing heat from the A/C condenser.

If the required fan stage is unavailable, the A/C may:

• Cool poorly at idle

• Cool poorly in traffic

• Lose cooling performance at low speed

• Cycle abnormally

• Temporarily shut down

Can P0695 Drain the Battery?

Potentially.

If the cooling fan remains running after the engine is switched off, prolonged operation can discharge the battery.

A continuously operating fan should therefore be investigated rather than simply ignored.

Can a Bad Cooling Fan Motor Cause P0695?

Possibly, but it should not be assumed.

P0695 identifies a low relay control circuit condition, not specifically a defective fan motor.

A failed motor can cause abnormal electrical behavior, but the relay-control circuit should be tested separately.

How Is P0695 Diagnosed?

A systematic electrical diagnosis is the best approach.

1. Scan all control modules

Record:

• Stored DTCs

• Pending DTCs

• Cooling-system codes

• Coolant-temperature codes

• Communication codes

Other codes may reveal the root cause.

2. Identify Cooling Fan 3

Use the vehicle's wiring diagram to determine exactly which relay, fan, or control stage is involved.

3. Inspect the fuse and relay box

Check for:

• Corrosion

• Water

• Heat damage

• Melted plastic

• Loose terminals

• Incorrect relay

4. Test the relay

Check the relay coil and switching contacts according to specifications.

5. Measure the control voltage

Measure the voltage in the Fan 3 relay control circuit.

Compare it with the manufacturer's expected value.

6. Check for a short to ground

Inspect the control wire for an unwanted ground connection.

7. Check for excessive resistance

A damaged wire or poor terminal can create voltage loss.

8. Inspect the harness

Look for:

• Chafing

• Pinching

• Melted insulation

• Broken wires

• Previous repairs

9. Test the fan motor

Verify that the motor can operate correctly when commanded.

10. Check the fan control module

If equipped, test its power, ground, inputs, and outputs.

11. Verify ECU operation

If all external circuits are correct, test the ECU's fan-control output.

Can a Multimeter Diagnose P0695?

Yes.

A multimeter can be used to check:

• Control-circuit voltage

• Relay coil resistance

• Voltage drop

• Continuity

• Battery voltage

• Short circuits

Voltage-drop testing is particularly useful for identifying poor connections that appear normal during a basic continuity test.

Can a Scan Tool Help?

Yes.

A capable scan tool may allow you to view:

• Fan command

• Fan status

• Engine coolant temperature

• Fan duty cycle

• Relay activation

Some vehicles also support an active test that allows the technician to command the cooling fan on and off.

This can help determine whether the ECU, relay, and fan respond correctly.

What If the Fan Does Not Run?

Check the complete circuit:

Fuse → Relay → Relay control → Fan motor → Ground

Also check:

• Fan control module

• ECU command

• Wiring

• Connectors

Do not automatically replace the fan motor.

What If the Fan Runs Normally?

A fan that works normally does not necessarily eliminate the electrical fault.

The problem may be intermittent or limited to a specific fan stage.

Check:

• Relay-control voltage

• Stored and pending codes

• Wiring

• Connector terminals

• ECU command

What If P0695 Appears With a Coolant Temperature Sensor Code?

This combination deserves attention.

The ECU uses coolant temperature information to determine when and how strongly the cooling fans should operate.

A faulty temperature sensor can therefore cause abnormal fan behavior.

If a coolant-temperature DTC is also present, both faults should be investigated together.

What If P0695 Appears After Engine Repair?

Inspect the engine-bay harness carefully.

Look for:

• Disconnected connectors

• Pinched wiring

• Damaged insulation

• Incorrect harness routing

• Loose grounds

Cooling-fan wiring can be disturbed during work around the radiator, engine, intake, or front body structure.

What If P0695 Appears After Electrical Work?

Check for:

• Incorrect relay

• Incorrect fuse

• Wiring modifications

• Added accessories

• Poor electrical repairs

A relay that looks physically correct may still have different electrical characteristics from the specified component.

Is P0695 a Serious Problem?

It can be.

The main concern is the possibility of engine overheating.

If the affected fan stage is required to control coolant temperature, continued operation with a faulty circuit can eventually cause:

• Excessive coolant temperature

• Cooling-system stress

• Head-gasket damage

• Cylinder-head damage

• Serious engine damage

Can You Drive With P0695?

If the engine remains at normal operating temperature and the cooling fans are functioning correctly, a short trip for diagnosis may be possible.

Monitor the temperature gauge carefully.

Do not continue driving if:

• The engine overheats

• The temperature warning light appears

• Steam is visible

• Coolant temperature rises rapidly

• The cooling fan does not operate when required

How Is P0695 Repaired?

The repair depends on the confirmed cause.

Possible repairs include:

• Replacing a defective cooling fan relay

• Repairing a shorted control wire

• Repairing damaged wiring

• Repairing connector terminals

• Replacing a damaged connector

• Repairing a cooling fan control module

• Replacing a failed fan motor

• Correcting an incorrect relay or wiring modification

• Repairing an ECU driver circuit

• Replacing the ECU only when internal failure is confirmed

Does P0695 Require Cooling Fan Replacement?

No.

The code specifically concerns the Fan 3 relay control circuit being low.

The fan motor may be perfectly functional.

The relay, wiring, connector, control module, or ECU output may be responsible.

Does P0695 Require Relay Replacement?

Not automatically.

The relay is one possible cause, but it should be tested.

A short to ground or damaged wiring can produce the same general condition.

Does P0695 Require ECU Replacement?

Usually not.

The ECU should be considered only after the external circuit has been properly tested.

Common Diagnostic Mistakes

Replacing the cooling fan immediately

The problem may be entirely electrical.

Replacing the relay without testing the control wire

A short to ground can remain and cause the same problem.

Ignoring the fan control module

Some vehicles use electronic fan controllers rather than simple relay systems.

Ignoring overheating

A relatively simple electrical fault can become an expensive engine problem if the cooling system cannot maintain temperature.

Ignoring other DTCs

Temperature-sensor or communication codes may explain the fan problem.

Replacing the ECU too early

External electrical faults should always be eliminated first.

P0694 vs. P0695 vs. P0696

These codes are closely related.

P0694 – Cooling Fan 2 Relay Control Circuit High

Indicates a high condition in the Cooling Fan 2 relay control circuit.

P0695 – Cooling Fan 3 Relay Control Circuit Low

Indicates a low condition in the Cooling Fan 3 relay control circuit.

P0696 – Cooling Fan 3 Relay Control Circuit High

Indicates a high condition in the Cooling Fan 3 relay control circuit.

The important distinction is:

P0695 → Fan 3 control circuit voltage too low

P0696 → Fan 3 control circuit voltage too high

How Do You Clear P0695?

The proper process is:

Scan all modules → Identify Fan 3 → Check fuse and relay → Measure control voltage → Check for short to ground → Inspect wiring → Test connectors → Test fan motor → Check fan control module → Verify ECU command → Repair the confirmed fault → Clear DTCs → Perform an active fan test → Road test → Rescan

If P0695 returns, the low-voltage condition in the Cooling Fan 3 relay control circuit has not been resolved.

Final Thoughts on P0695

P0695 – Cooling Fan 3 Relay Control Circuit Low indicates that the ECU has detected lower-than-expected voltage in the electrical control circuit for Cooling Fan 3.

The cause may be a faulty relay, short to ground, damaged wiring, excessive resistance, poor connector, cooling fan control module problem, incorrect electrical modification, or, less commonly, an ECU driver fault.

The meaning of “Fan 3” varies between vehicles. It may refer to a third physical fan, a relay, or a specific fan-speed stage.

The best diagnostic approach is:

Identify Fan 3 → Check the relay → Measure control voltage → Check for short to ground → Inspect wiring and connectors → Test the fan → Check the fan-control module → Verify ECU operation.

Most importantly, P0695 does not automatically mean the cooling fan motor needs to be replaced. Because this is specifically a low relay-control circuit code, the electrical control circuit should be diagnosed before replacing major components.