Is a Bad Relay Causing Your Accord's Electrical Problems?

How to Fix Relay Issues

For 2020 Honda Accord owners, a failing relay can be the source of frustrating electrical gremlins, from a car that won't start to mysterious battery drains. While not the most common failure point, relays are critical switches that control high-current circuits for components like the starter, fans, and lights. When they fail, they can cause a range of confusing symptoms. As one owner troubleshooting a parasitic drain advised, “I’d also recommend pulling the underhood relays as well since I’ve had them fail and keep things energized when they shouldn’t be.” This guide will walk you through identifying and resolving relay-related problems based on real owner experiences.

Symptoms

The symptoms of a faulty relay in your vehicle can vary widely depending on which circuit it controls. The most common and alarming symptom is a no-start condition, often accompanied by a rapid clicking noise when you turn the key. This classic sound is the starter solenoid engaging and disengaging rapidly because it's not receiving sufficient power, which can point to a failing starter relay or a related power circuit issue.

Another frequent complaint is a parasitic battery drain. You might find your battery dead after the car sits overnight, even though you're sure you didn't leave any lights on. A stuck relay can keep a component—like a fan, pump, or control module—powered up even when the ignition is off, slowly sapping the battery's life. Owners have specifically mentioned checking relays when hunting for these elusive drains.

Other symptoms are more component-specific. You might notice your air conditioning condenser fan not turning on, leading to poor A/C performance and potential overheating. Intermittent operation of accessories like fog lights or erratic behavior from electronic modules can also be traced back to a flaky relay. Sometimes, the issue is subtle; as one owner shared while diagnosing a no-start, "Battery tested good, fuses and relays looked good, alternator tested good, all the wiring that I checked looked and tested good, etc etc." This highlights that a visual inspection isn't always enough—a relay can look perfect but still be faulty internally.

Most Likely Cause

The primary cause of relay failure is internal wear and contact degradation. A relay is an electromechanical switch. Over thousands of cycles, the small internal contacts that carry the electrical current can become pitted, corroded, or carbon-fouled. This increases resistance, which can cause voltage drop, overheating, and ultimately a failure to make a proper connection. A relay can fail in several ways: it can become stuck open (preventing any power from flowing), stuck closed (causing a parasitic drain), or become intermittent.

Environmental factors under the hood accelerate this wear. Heat from the engine, vibration, and moisture can all compromise the relay's internal components and its external electrical connections. While owners have mentioned checking for broader issues like an intake leak in the context of running problems, a failing relay itself is typically a standalone component failure. The key is that when a high-current circuit like the starter or a cooling fan malfunctions, the relay controlling that circuit should be one of the first suspects checked.

How to Diagnose

Diagnosing a bad relay requires a methodical approach, starting with the simplest checks. You'll need a basic multimeter, and for parasitic drain testing, one that can measure milliamps (mA) is essential.

1. Identify the Suspect Relay: Consult your owner's manual to locate the under-hood fuse/relay box. The diagram on the box lid or in the manual will identify which relay controls which component (e.g., "Starter Cut," "Condenser Fan," "A/C Compressor"). If the diagram is unclear, as one owner noted ("JDM no explanation on the fuse box lol"), you may need to search for a service manual or reliable online resource specific to the 2020 Accord.

2. The Swap Test (Easiest Method): Find another relay in the box with the same part number (often used for identical, non-critical circuits). Swap the suspect relay with a known good one from another location. If the problem (e.g., no-start, fan not working) moves with the relay, you've found the culprit. This is a quick and effective first step.

3. Listen and Feel: With the help of an assistant, have them turn the key to "START" or activate the component (like turning on the A/C). Place your fingers on the suspect relay. You should feel and hear a distinct, solid "click" as it engages. If you feel a weak chatter or no click at all, the relay's coil or the control signal may be faulty.

4. Electrical Testing with a Multimeter:

• Testing the Control Circuit (Coil): Set your multimeter to resistance (Ohms). Pull the relay out and identify the two smaller terminals (usually 85 and 86). You should read a resistance, typically between 50-150 ohms. An infinite reading (OL) means the coil is open and the relay is bad. A reading of 0 ohms means it's shorted.
• Testing the Load Circuit (Contacts): Set the multimeter to continuity or resistance. The two larger terminals (usually 30 and 87) should show no continuity (open circuit) when the relay is at rest. You can then apply 12 volts from the battery to the small coil terminals (85 and 86). You should hear a click, and the multimeter should now show continuity (near 0 ohms) between the large terminals (30 and 87). If it doesn't, the contacts are faulty.

5. Testing for Parasitic Drain: If you have a battery drain, this is a more involved process. As owner Lxiflyby detailed, “Don’t forget the dome lights/doors open will draw current and also the modules may need to go to sleep and it may take up to 15-20 minutes for that to occur.” After ensuring all doors are closed and the vehicle is in sleep mode, you can systematically pull relays one by one while monitoring the drain with a multimeter in series with the battery. When pulling a specific relay causes a significant drop in the drain current, you've likely found the circuit with the problem.

Step-by-Step Fix

Replacing a faulty relay is one of the simplest DIY repairs. Here’s how to do it safely and correctly.

Step 1: Safety First. Ensure the vehicle is parked on a level surface with the parking brake engaged. Turn the ignition completely OFF and remove the key.

Step 2: Locate the Faulty Relay. Based on your diagnosis, identify the exact relay. For common issues like a no-start, this is typically the "Starter Cut" or "Main" relay. For A/C fan issues, it's the "Condenser Fan" or "Radiator Fan" relay. Refer to your manual for the precise location.

Step 3: Remove the Old Relay. Relays are simply pulled straight up and out of their sockets. Do not twist or rock it excessively. If it's stuck, you can use a small relay puller tool or gently wiggle it side-to-side while pulling upward. Inspect the relay's terminals and the socket for any signs of corrosion, melting, or damage. Clean the socket with electrical contact cleaner if needed.

Step 4: Install the New Relay. Ensure the new relay is an exact match. It must have the same terminal configuration (pinout) and amperage rating. Align the pins with the socket and press down firmly until it seats completely. You should hear a soft click.

Step 5: Test the Repair. Before reassembling anything, test the fix. Try to start the car or activate the component that was malfunctioning. Listen for the relay's click and verify normal operation.

Step 6: Clear Codes (If Necessary). If the check engine light was on due to the fault (e.g., from a cooling fan circuit), you may need to clear the code with an OBD-II scanner or by disconnecting the battery for a few minutes. Note that disconnecting the battery may reset radio presets and other memory.

Step 7: Monitor the System. Over the next few days, pay attention to the system you repaired. Ensure the battery holds a charge overnight and that the component operates reliably every time. As one owner wisely cautioned during a wiring modification, proper connection is key: "Cut the fog light wire anyplace convenient and attach to both sides of the power leg (87 and 30, polarity doesn't matter) and attach a ground wire to whichever leg is still open (85 or 86)." While this quote is about adding a relay, it underscores the importance of correct terminal identification for any relay work.

Parts and Tools Needed

• Replacement Relay: Must be specific to your 2020 Honda Accord. A common OEM part number is 38233-TBA-A01 (often labeled as a "Multi-Purpose Relay"), but this can vary by location in the fuse box. Always cross-reference the number printed on your old relay or consult a dealership parts desk. Cost: $15 - $35.
• Basic Multimeter: For testing voltage, resistance, and continuity. A digital model is preferred.
• Relay Puller Tool (Optional): A small plastic tool that makes removing tight relays easier without damaging them.
• Electrical Contact Cleaner: To clean corrosion from the relay socket if present.
• Owner's Manual or Service Manual: For the fuse/relay box diagram.
• Safety Glasses & Gloves: Simple protection is always a good idea.

Real Owner Costs

The cost to fix a relay issue is generally low, but it depends entirely on the diagnosis path.

DIY Repair: This is the most cost-effective route if you can identify the bad relay yourself.

• Parts Only: $15 - $35 for a single OEM-quality relay.
• Total DIY Cost: $15 - $35. Your only expense is the part.

Professional Diagnosis and Repair: Costs rise significantly due to shop labor rates, especially if the problem is intermittent or requires parasitic draw testing.

• Diagnostic Fee: Most shops charge 1 hour of labor to diagnose an electrical issue. Average rate: $100 - $150.
• Parts Cost: Relay marked up to $25 - $50.
• Labor to Replace: 0.3 hours (approx. 20 minutes). Labor cost: $30 - $45.
• Total Professional Cost: $155 - $245. This aligns with owner experiences where they spent time checking multiple systems themselves before pinpointing the issue. As one owner deep in diagnostics reflected, "Only thing I haven't checked is the starter yet because I haven't gotten under the vehicle yet and I didn't want to take off the intake inlet and battery yet if it was just the terminals," illustrating how a simple relay check can save hours of more invasive labor.

Prevention

While relays will eventually wear out, you can prolong their life and prevent related issues.

• Keep the Engine Bay Clean: Periodically clean the under-hood fuse/relay box area to prevent dirt and moisture accumulation, which can lead to terminal corrosion.
• Secure Aftermarket Accessories: If you install aftermarket lights, stereos, or other electronics, ensure they are wired properly through a dedicated relay and fuse. Poor aftermarket installations are a common source of electrical faults.
• Address Electrical Issues Promptly: If you notice intermittent operation of any component, investigate it sooner rather than later. A failing relay can sometimes overheat and damage the socket.
• Battery Maintenance: A weak or failing battery can cause low voltage conditions that make relays chatter and wear out prematurely. Ensure your battery terminals are clean and tight, and have the battery tested annually.

What Owners Say

Real experiences from HONDA owners:

Success Stories

"I replaced the relay and it worked for a few days but now I’m back to square one. I took it to a shop and when they wired the clutch coil directly to the battery it would blow out cold air." — Holduhn (source)

"There are some diagnostic you can do yourself though, here are a few: I second that it sounds like it's electric. If it worked after replacing the relay, first replace the relay (or test it if you know how to test a relay) in the odd chance that the new relay was weak and defective and it blew out quickly." — Miami13 (source)

"If it worked after replacing the relay, first replace the relay (or test it if you know how to test a relay) in the odd chance that the new relay was weak and defective and it blew out quickly." — Miami13 (source)

Owner Experiences

"This wire won't carry much current so it's size doesn't matter. Cut the fog light wire anyplace convenient and attach to both sides of the power leg (87 and 30, polarity doesn't matter) and attach a ground wire to whichever leg is still open (85 or 86)." — dacaur (source)

"Cut the fog light wire anyplace convenient and attach to both sides of the power leg (87 and 30, polarity doesn't matter) and attach a ground wire to whichever leg is still open (85 or 86)." — dacaur (source)

"Keep disconnecting things until it goes away. I’d also recommend pulling the underwood relays as well since I’ve had them fail and keep things energized when they shouldn’t be." — Lxiflyby (source)

Lessons Learned

⚠️ "I doubt it will be the start button, as you seem to still get it to reliably go into accessories and ignition modes - just not the start function. If you had to keep pressing it to get into accessories, then I would suspect the start button." — commodorenut (source)

⚠️ "It is very likely to be the culprit based on everything else you have done. I doubt it will be the start button, as you seem to still get it to reliably go into accessories and ignition modes - just not the start function." — commodorenut (source)

⚠️ "I just had O'Reilly's come out and test it and they said everything was fine. The battery is corrosion-free. also update I replaced the starter motor and I'm still having intermittent starting and now I'm thinking it's the relay." — JacobH (source)

FAQ

Q: How long does it take to replace a bad relay? A: The physical replacement takes less than 5 minutes. The vast majority of your time will be spent correctly diagnosing which relay is faulty. A simple swap test can be done in 2 minutes, while a full parasitic draw diagnosis could take an hour or more.

Q: Can I drive with a faulty relay? A: It depends entirely on which relay has failed. A failed starter relay means you cannot drive at all. A failed cooling fan relay could lead to engine overheating, especially in traffic or hot weather, which can cause severe engine damage. A relay causing a parasitic drain will leave you with a dead battery. It's best to address the issue immediately.

Q: Is this a common issue on the 2020 Accord? A: Based on owner discussions, relay failure is not among the most widespread chronic issues for this model year. However, as with any vehicle, relays are wear items and can fail randomly. The "starter plague" mentioned by some owners often points to wiring or the starter motor itself, but the relay is a logical and easy first check.

Q: DIY vs mechanic—what's recommended? A: If the symptom is obvious (e.g., a single component doesn't work and a swap test confirms the relay is bad), this is a perfect DIY job. If you are dealing with an intermittent no-start, check engine light, or a battery drain, the diagnosis becomes more complex. As owner bluewizard8877 noted, "Your starter could be going out on you... Batteries can test as good but still not be good enough." If you're not comfortable with a multimeter or systematic diagnosis, paying for a professional diagnostic fee can save you time, money on incorrect parts, and frustration.

Q: Can a bad relay cause a check engine light? A: Yes. If a relay controls a component monitored by the engine computer (PCM)—such as the evaporative emissions (EVAP) purge valve, cooling fans, or fuel pump—its failure can cause a circuit malfunction code (e.g., P0691 "Fan 1 Control Circuit").

Q: Are all the relays under the hood the same? A: No. While many may share the same physical size and base part number, they are often configured for different amperage ratings or have internal diode/resistor differences. Always replace a relay with an identical part. Using an incorrect relay can lead to component failure or electrical damage.