What is the alc comp fuse?

The A/C compressor fuse is the protective power fuse for the air conditioning compressor clutch circuit in a vehicle. It safeguards wiring and the clutch coil from overload; if the fuse blows, the AC compressor typically won’t engage.

How the A/C compressor fuse works

The vehicle’s climate control system uses a relay to energize the A/C compressor clutch when cooling is requested. Power to the clutch coil passes through the A/C fuse, so the fuse acts as a safety device. If a short, overload, or fault occurs in the circuit, the fuse blows to prevent wiring damage or a blown fuse from affecting other circuits.

Where it’s located and how to identify it

Most cars place the A/C fuse in one of two places: the engine bay fuse box or the interior fuse panel. Fuses are labeled on the diagram inside the fuse box cover or in the owner's manual. Common labels include “A/C,” “A/C COMP,” “AC CLUTCH,” or “A/C PWR.” Always verify the exact location and rating for your specific model.

Typical ratings and identification

Fuse ratings for A/C compressor circuits vary by vehicle, but you’ll often see values around 7.5A, 10A, 15A, or sometimes 20A. Using the exact rating specified for your vehicle is important to avoid nuisance blows or wiring damage. The rating is printed on the fuse itself and included in the fuse diagram.

Common fuse ratings you might encounter for A/C compressor circuits include the following:

• 7.5A fuses, found in some older or smaller vehicles


• 10A fuses, widely used across many passenger cars


• 15A fuses, used in models with higher electrical loads


• 20A fuses, used in trucks or vehicles with robust electrical systems

Knowing the exact rating for your vehicle is essential; consult the owner's manual or the fuse diagram to confirm the correct value before replacing a blown fuse.

Symptoms of a blown A/C fuse

If the fuse is blown, the A/C system will generally fail to engage or provide cooling. Look for these signs:

• A/C compressor clutch does not engage when you turn on cooling


• No cooling or reduced cooling performance


• Electrical or burning odor near the fuse box (rare but possible if a short occurred)


• A fuse visibly blown or discolored from its protective housing


• Clicking relay without compressor engagement (if the relay is stuck or not energizing)

If you notice these symptoms, don’t assume it’s simply low refrigerant; a blown fuse points to an electrical issue that should be diagnosed to avoid further damage.

Steps to diagnose and replace the A/C fuse

Use these steps to safely inspect and, if appropriate, replace the A/C fuse. Always refer to your vehicle’s manual for model-specific instructions.

1. Turn off the ignition and disconnect the battery negative terminal to prevent accidental shorts.


2. Locate the correct fuse box (engine bay or interior) and identify the fuse labeled for the A/C circuit using the diagram.


3. Remove the fuse with a fuse puller or needle-nose pliers and visually inspect it. A blown fuse will have a broken conductor inside or a darkened appearance.


4. If you have a spare of the same rating, replace the fuse with a new one of the exact amperage. Do not substitute a higher or lower value.


5. After replacing, reconnect the battery, start the engine, and test the A/C to see if the compressor engages and cooling returns.


6. If the new fuse blows again or the compressor still won’t engage, there is likely an underlying problem (shorted clutch coil, wiring damage, faulty relay, overheated compressor, or a seized compressor). Stop driving the vehicle and seek professional diagnosis.

When diagnosing, consider inspecting related components such as the A/C relay, wiring harness to the compressor clutch, and any pressure switches or control modules that could affect the circuit.

When to seek professional help

If you’re not comfortable with auto electrical work or the fuse keeps blowing after replacement, consult a qualified mechanic or automotive electrician. Repeated fuse failures can indicate a more serious problem in the A/C circuitry or compressor itself, and diagnosing electrical faults requires proper tools and safety precautions.

Summary

The A/C compressor fuse protects the circuit that powers the A/C clutch, preventing wiring damage from overcurrent. It’s commonly found in the engine bay or interior fuse boxes and labeled as A/C or AC COMP, with typical ratings ranging from 7.5A to 20A depending on the vehicle. A blown fuse disables the compressor engagement and cooling, but repeated failures point to a deeper electrical issue that should be inspected by a professional. Always verify the exact fuse rating for your model before replacement and follow safe diagnostic steps.

How to tell if an air compressor fuse is blown?

Always turn off the power to the AC system at the breaker box before attempting any inspection. Using a multimeter, you can test the fuse for continuity. If the meter reads zero or doesn't move, the fuse is blown.

What happens if the BCM fuse blows?

If a Body Control Module (BCM) fuse blows, various electrical systems will malfunction because the BCM controls many vehicle electronics like lights, power windows, and wipers. This can range from minor issues to a complete loss of functionality, and a repeatedly blowing fuse indicates a short circuit or a faulty BCM itself that needs professional diagnosis.
 
This video explains the symptoms of a bad Body Control Module (BCM): 1mSimple Car SolutionsYouTube · Aug 15, 2025
Immediate effects

• Malfunctioning lights: Headlights, taillights, turn signals, and interior dome lights may not work correctly, or they might stay on constantly.
• Window and lock problems: Power windows, door locks, and the horn may stop working or behave erratically.
• Wiper issues: Windshield wipers may become inoperable.
• Other electrical problems: The air conditioning, security system, and driver assist systems can also be affected. 

If the fuse blows repeatedly

• Indication of a deeper problem: A recurring blown fuse is not a simple electrical failure but a symptom of a more serious issue, most likely a short circuit. 
• Potential causes: The short circuit could be caused by damaged wiring (e.g., due to corrosion or physical damage) or a faulty relay or switch connected to the BCM. 
• Can prevent the engine from starting: A faulty BCM can disrupt communication with the engine control module, preventing the engine from starting. This can sometimes be accompanied by an immobilizer lockout, like the Passlock system in some vehicles. 

This video demonstrates how to identify if a fuse is blown: 54sE H Car_net YouTube · Oct 7, 2025
What to do

• Do not keep replacing the fuse: Replacing the fuse with the correct amperage is necessary to temporarily restore power, but if it blows again, don't just keep replacing it. 
• Inspect wiring: Visually inspect the wiring harnesses for any signs of damage, pinched wires, or corrosion. 
• Check relays and connectors: Check any relays, switches, and connectors associated with the BCM for faults, poor connections, or corrosion. 
• Seek professional help: A professional can use diagnostic tools to scan for trouble codes (like U0140, which indicates lost communication with the BCM) and use a multimeter to pinpoint the exact source of the short circuit. 

What is an anl fuse used for?

An ANL fuse is a high-current circuit protection device designed for applications requiring robust and reliable overcurrent protection. These fuses are commonly used in environments such as forklifts, marine systems, aviation, and battery charging setups, where high electrical loads demand fast-acting safeguards.

How to know if an ECM fuse is blown?

If an ECM fuse blows, it can lead to several noticeable symptoms. These can range from engine stalling, rough idling, to loss of power. One might also observe the dreaded check engine light as the vehicle's onboard diagnostics system registers error codes related to the electrical setback.